diff --git a/DOCKER/docker.sh b/DOCKER/docker.sh
index d64557a1..d2eb1471 100755
--- a/DOCKER/docker.sh
+++ b/DOCKER/docker.sh
@@ -8,11 +8,6 @@ docker build -t tmbase -f Dockerfile .
 # (config and blockchain data go in here)
 docker run --name tmdata --entrypoint /bin/echo tmbase Data-only container for tmnode
 
-# Copy files into the data-only container
-# You should stop the containers before running this
-#   cd $DATA_SRC
-#   tar cf - . | docker run -i --rm --volumes-from mintdata mint tar xvf - -C /data/tendermint
-
 # Run tendermint node
 docker run --name tmnode --volumes-from tmdata -d -p 46656:46656 -p 46657:46657 -e TMSEEDS="goldenalchemist.chaintest.net:46657" -e TMNAME="testnode" -e TMREPO="github.com/tendermint/tendermint" -e TMHEAD="origin/develop" tmbase
 
diff --git a/cmd/tendermint/main.go b/cmd/tendermint/main.go
index 81c55f32..64ac87e5 100644
--- a/cmd/tendermint/main.go
+++ b/cmd/tendermint/main.go
@@ -35,6 +35,12 @@ Commands:
 	switch args[0] {
 	case "node":
 		node.RunNode()
+	case "replay":
+		if len(args) > 1 && args[1] == "console" {
+			node.RunReplayConsole()
+		} else {
+			node.RunReplay()
+		}
 	case "init":
 		init_files()
 	case "show_validator":
diff --git a/config/tendermint/config.go b/config/tendermint/config.go
index b2e220fc..bdeb6add 100644
--- a/config/tendermint/config.go
+++ b/config/tendermint/config.go
@@ -67,6 +67,7 @@ func GetConfig(rootDir string) cfg.Config {
 	mapConfig.SetDefault("rpc_laddr", "0.0.0.0:46657")
 	mapConfig.SetDefault("prof_laddr", "")
 	mapConfig.SetDefault("revision_file", rootDir+"/revision")
+	mapConfig.SetDefault("cswal", rootDir+"/cswal")
 	return mapConfig
 }
 
diff --git a/config/tendermint_test/config.go b/config/tendermint_test/config.go
index 82047ded..3ded9b1e 100644
--- a/config/tendermint_test/config.go
+++ b/config/tendermint_test/config.go
@@ -57,9 +57,8 @@ func initTMRoot(rootDir string) {
 	if !FileExists(genesisFilePath) {
 		MustWriteFile(genesisFilePath, []byte(defaultGenesis), 0644)
 	}
-	if !FileExists(privFilePath) {
-		MustWriteFile(privFilePath, []byte(defaultPrivValidator), 0644)
-	}
+	// we always overwrite the priv val
+	MustWriteFile(privFilePath, []byte(defaultPrivValidator), 0644)
 }
 
 func GetConfig(rootDir string) cfg.Config {
@@ -92,6 +91,7 @@ func GetConfig(rootDir string) cfg.Config {
 	mapConfig.SetDefault("rpc_laddr", "0.0.0.0:36657")
 	mapConfig.SetDefault("prof_laddr", "")
 	mapConfig.SetDefault("revision_file", rootDir+"/revision")
+	mapConfig.SetDefault("cswal", rootDir+"/cswal")
 	return mapConfig
 }
 
diff --git a/consensus/common.go b/consensus/common.go
new file mode 100644
index 00000000..ec1a0fa9
--- /dev/null
+++ b/consensus/common.go
@@ -0,0 +1,15 @@
+package consensus
+
+import (
+	"github.com/tendermint/go-events"
+)
+
+// NOTE: this is blocking
+func subscribeToEvent(evsw *events.EventSwitch, receiver, eventID string, chanCap int) chan interface{} {
+	// listen for new round
+	ch := make(chan interface{}, chanCap)
+	evsw.AddListenerForEvent(receiver, eventID, func(data events.EventData) {
+		ch <- data
+	})
+	return ch
+}
diff --git a/consensus/common_test.go b/consensus/common_test.go
index c70db420..08912665 100644
--- a/consensus/common_test.go
+++ b/consensus/common_test.go
@@ -140,7 +140,7 @@ func addVoteToFromMany(to *ConsensusState, votes []*types.Vote, froms ...*valida
 func addVoteToFrom(to *ConsensusState, from *validatorStub, vote *types.Vote) {
 	valIndex, _ := to.Validators.GetByAddress(from.PrivValidator.Address)
 
-	to.peerMsgQueue <- msgInfo{msg: &VoteMessage{valIndex, vote}}
+	to.peerMsgQueue <- msgInfo{Msg: &VoteMessage{valIndex, vote}}
 	// added, err := to.TryAddVote(valIndex, vote, "")
 	/*
 		if _, ok := err.(*types.ErrVoteConflictingSignature); ok {
@@ -296,16 +296,16 @@ func validatePrevoteAndPrecommit(t *testing.T, cs *ConsensusState, thisRound, lo
 	cs.mtx.Unlock()
 }
 
-func simpleConsensusState(nValidators int) (*ConsensusState, []*validatorStub) {
-	// Get State
-	state, privVals := randGenesisState(nValidators, false, 10)
+func fixedConsensusState() *ConsensusState {
+	stateDB := dbm.NewMemDB()
+	state := sm.MakeGenesisStateFromFile(stateDB, config.GetString("genesis_file"))
+	privValidatorFile := config.GetString("priv_validator_file")
+	privValidator := types.LoadOrGenPrivValidator(privValidatorFile)
+	return newConsensusState(state, privValidator)
 
-	// fmt.Println(state.Validators)
-
-	vss := make([]*validatorStub, nValidators)
-
-	// make consensus state for lead validator
+}
 
+func newConsensusState(state *sm.State, pv *types.PrivValidator) *ConsensusState {
 	// Get BlockStore
 	blockDB := dbm.NewMemDB()
 	blockStore := bc.NewBlockStore(blockDB)
@@ -320,14 +320,21 @@ func simpleConsensusState(nValidators int) (*ConsensusState, []*validatorStub) {
 
 	// Make ConsensusReactor
 	cs := NewConsensusState(state, proxyAppConnCon, blockStore, mempool)
-	cs.SetPrivValidator(privVals[0])
+	cs.SetPrivValidator(pv)
 
 	evsw := events.NewEventSwitch()
 	cs.SetEventSwitch(evsw)
 	evsw.Start()
+	return cs
+}
 
-	// start the transition routines
-	//	cs.startRoutines()
+func randConsensusState(nValidators int) (*ConsensusState, []*validatorStub) {
+	// Get State
+	state, privVals := randGenesisState(nValidators, false, 10)
+
+	vss := make([]*validatorStub, nValidators)
+
+	cs := newConsensusState(state, privVals[0])
 
 	for i := 0; i < nValidators; i++ {
 		vss[i] = NewValidatorStub(privVals[i])
@@ -344,7 +351,7 @@ func subscribeToVoter(cs *ConsensusState, addr []byte) chan interface{} {
 	go func() {
 		for {
 			v := <-voteCh0
-			vote := v.(*types.EventDataVote)
+			vote := v.(types.EventDataVote)
 			// we only fire for our own votes
 			if bytes.Equal(addr, vote.Address) {
 				voteCh <- v
@@ -386,13 +393,3 @@ func startTestRound(cs *ConsensusState, height, round int) {
 	cs.enterNewRound(height, round)
 	cs.startRoutines(0)
 }
-
-// NOTE: this is blocking
-func subscribeToEvent(evsw *events.EventSwitch, receiver, eventID string, chanCap int) chan interface{} {
-	// listen for new round
-	ch := make(chan interface{}, chanCap)
-	evsw.AddListenerForEvent(receiver, eventID, func(data events.EventData) {
-		ch <- data
-	})
-	return ch
-}
diff --git a/consensus/reactor.go b/consensus/reactor.go
index 493fb2e2..8f4cacee 100644
--- a/consensus/reactor.go
+++ b/consensus/reactor.go
@@ -240,7 +240,7 @@ func (conR *ConsensusReactor) registerEventCallbacks() {
 	})
 
 	conR.evsw.AddListenerForEvent("conR", types.EventStringVote(), func(data events.EventData) {
-		edv := data.(*types.EventDataVote)
+		edv := data.(types.EventDataVote)
 		conR.broadcastHasVoteMessage(edv.Vote, edv.Index)
 	})
 }
diff --git a/consensus/replay.go b/consensus/replay.go
new file mode 100644
index 00000000..2de357b2
--- /dev/null
+++ b/consensus/replay.go
@@ -0,0 +1,360 @@
+package consensus
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"reflect"
+	"strconv"
+	"strings"
+	"time"
+
+	. "github.com/tendermint/go-common"
+	"github.com/tendermint/go-wire"
+
+	sm "github.com/tendermint/tendermint/state"
+	"github.com/tendermint/tendermint/types"
+)
+
+// unmarshal and apply a single message to the consensus state
+func (cs *ConsensusState) readReplayMessage(msgBytes []byte, newStepCh chan interface{}) error {
+	var err error
+	var msg ConsensusLogMessage
+	wire.ReadJSON(&msg, msgBytes, &err)
+	if err != nil {
+		fmt.Println(string(msgBytes))
+		return fmt.Errorf("Error reading json data: %v", err)
+	}
+
+	// for logging
+	switch m := msg.Msg.(type) {
+	case types.EventDataRoundState:
+		log.Notice("New Step", "height", m.Height, "round", m.Round, "step", m.Step)
+		// these are playback checks
+		ticker := time.After(time.Second * 2)
+		if newStepCh != nil {
+			select {
+			case mi := <-newStepCh:
+				m2 := mi.(types.EventDataRoundState)
+				if m.Height != m2.Height || m.Round != m2.Round || m.Step != m2.Step {
+					return fmt.Errorf("RoundState mismatch. Got %v; Expected %v", m2, m)
+				}
+			case <-ticker:
+				return fmt.Errorf("Failed to read off newStepCh")
+			}
+		}
+	case msgInfo:
+		peerKey := m.PeerKey
+		if peerKey == "" {
+			peerKey = "local"
+		}
+		switch msg := m.Msg.(type) {
+		case *ProposalMessage:
+			p := msg.Proposal
+			log.Notice("Proposal", "height", p.Height, "round", p.Round, "header",
+				p.BlockPartsHeader, "pol", p.POLRound, "peer", peerKey)
+		case *BlockPartMessage:
+			log.Notice("BlockPart", "height", msg.Height, "round", msg.Round, "peer", peerKey)
+		case *VoteMessage:
+			v := msg.Vote
+			log.Notice("Vote", "height", v.Height, "round", v.Round, "type", v.Type,
+				"hash", v.BlockHash, "header", v.BlockPartsHeader, "peer", peerKey)
+		}
+		// internal or from peer
+		if m.PeerKey == "" {
+			cs.internalMsgQueue <- m
+		} else {
+			cs.peerMsgQueue <- m
+		}
+	case timeoutInfo:
+		log.Notice("Timeout", "height", m.Height, "round", m.Round, "step", m.Step, "dur", m.Duration)
+		cs.tockChan <- m
+	default:
+		return fmt.Errorf("Unknown ConsensusLogMessage type: %v", reflect.TypeOf(msg.Msg))
+	}
+	return nil
+}
+
+// replay only those messages since the last block
+func (cs *ConsensusState) catchupReplay(height int) error {
+	if cs.wal == nil {
+		log.Warn("consensus msg log is nil")
+		return nil
+	}
+	if !cs.wal.exists {
+		// new wal, nothing to catchup on
+		return nil
+	}
+
+	// starting from end of file,
+	// read messages until a new height is found
+	nLines, err := cs.wal.SeekFromEnd(func(lineBytes []byte) bool {
+		var err error
+		var msg ConsensusLogMessage
+		wire.ReadJSON(&msg, lineBytes, &err)
+		if err != nil {
+			panic(Fmt("Failed to read cs_msg_log json: %v", err))
+		}
+		m, ok := msg.Msg.(types.EventDataRoundState)
+		if ok && m.Step == RoundStepNewHeight.String() {
+			// TODO: ensure the height matches
+			return true
+		}
+		return false
+	})
+
+	if err != nil {
+		return err
+	}
+
+	var beginning bool // if we had to go back to the beginning
+	if c, _ := cs.wal.fp.Seek(0, 1); c == 0 {
+		beginning = true
+	}
+
+	log.Notice("Catchup by replaying consensus messages", "n", nLines)
+
+	// now we can replay the latest nLines on consensus state
+	// note we can't use scan because we've already been reading from the file
+	reader := bufio.NewReader(cs.wal.fp)
+	for i := 0; i < nLines; i++ {
+		msgBytes, err := reader.ReadBytes('\n')
+		if err == io.EOF {
+			break
+		} else if err != nil {
+			return err
+		} else if len(msgBytes) == 0 {
+			continue
+		}
+		// the first msg is (usually) the NewHeight event, so we can ignore it
+		if !beginning && i == 1 {
+			continue
+		}
+
+		// NOTE: since the priv key is set when the msgs are received
+		// it will attempt to eg double sign but we can just ignore it
+		// since the votes will be replayed and we'll get to the next step
+		if err := cs.readReplayMessage(msgBytes, nil); err != nil {
+			return err
+		}
+	}
+	log.Info("Done catchup replay")
+	return nil
+}
+
+//--------------------------------------------------------
+// replay messages interactively or all at once
+
+// Interactive playback
+func (cs ConsensusState) ReplayConsole(file string) error {
+	return cs.replay(file, true)
+}
+
+// Full playback, with tests
+func (cs ConsensusState) ReplayMessages(file string) error {
+	return cs.replay(file, false)
+}
+
+// replay all msgs or start the console
+func (cs *ConsensusState) replay(file string, console bool) error {
+	if cs.IsRunning() {
+		return errors.New("cs is already running, cannot replay")
+	}
+	if cs.wal != nil {
+		return errors.New("cs wal is open, cannot replay")
+	}
+
+	cs.startForReplay()
+
+	// ensure all new step events are regenerated as expected
+	newStepCh := subscribeToEvent(cs.evsw, "replay-test", types.EventStringNewRoundStep(), 1)
+
+	// just open the file for reading, no need to use wal
+	fp, err := os.OpenFile(file, os.O_RDONLY, 0666)
+	if err != nil {
+		return err
+	}
+
+	pb := newPlayback(file, fp, cs, cs.state.Copy())
+	defer pb.fp.Close()
+
+	var nextN int // apply N msgs in a row
+	for pb.scanner.Scan() {
+		if nextN == 0 && console {
+			nextN = pb.replayConsoleLoop()
+		}
+
+		if err := pb.cs.readReplayMessage(pb.scanner.Bytes(), newStepCh); err != nil {
+			return err
+		}
+
+		if nextN > 0 {
+			nextN -= 1
+		}
+		pb.count += 1
+	}
+	return nil
+}
+
+//------------------------------------------------
+// playback manager
+
+type playback struct {
+	cs *ConsensusState
+
+	fp      *os.File
+	scanner *bufio.Scanner
+	count   int // how many lines/msgs into the file are we
+
+	// replays can be reset to beginning
+	fileName     string    // so we can close/reopen the file
+	genesisState *sm.State // so the replay session knows where to restart from
+}
+
+func newPlayback(fileName string, fp *os.File, cs *ConsensusState, genState *sm.State) *playback {
+	return &playback{
+		cs:           cs,
+		fp:           fp,
+		fileName:     fileName,
+		genesisState: genState,
+		scanner:      bufio.NewScanner(fp),
+	}
+}
+
+// go back count steps by resetting the state and running (pb.count - count) steps
+func (pb *playback) replayReset(count int, newStepCh chan interface{}) error {
+
+	pb.cs.Stop()
+
+	newCs := NewConsensusState(pb.genesisState.Copy(), pb.cs.proxyAppConn, pb.cs.blockStore, pb.cs.mempool)
+	newCs.SetEventSwitch(pb.cs.evsw)
+
+	newCs.startForReplay()
+
+	pb.fp.Close()
+	fp, err := os.OpenFile(pb.fileName, os.O_RDONLY, 0666)
+	if err != nil {
+		return err
+	}
+	pb.fp = fp
+	pb.scanner = bufio.NewScanner(fp)
+	count = pb.count - count
+	log.Notice(Fmt("Reseting from %d to %d", pb.count, count))
+	pb.count = 0
+	pb.cs = newCs
+	for i := 0; pb.scanner.Scan() && i < count; i++ {
+		if err := pb.cs.readReplayMessage(pb.scanner.Bytes(), newStepCh); err != nil {
+			return err
+		}
+		pb.count += 1
+	}
+	return nil
+}
+
+func (cs *ConsensusState) startForReplay() {
+	cs.BaseService.OnStart()
+	go cs.receiveRoutine(0)
+	// since we replay tocks we just ignore ticks
+	go func() {
+		for {
+			select {
+			case <-cs.tickChan:
+			case <-cs.Quit:
+				return
+			}
+		}
+	}()
+}
+
+// console function for parsing input and running commands
+func (pb *playback) replayConsoleLoop() int {
+	for {
+		fmt.Printf("> ")
+		bufReader := bufio.NewReader(os.Stdin)
+		line, more, err := bufReader.ReadLine()
+		if more {
+			Exit("input is too long")
+		} else if err != nil {
+			Exit(err.Error())
+		}
+
+		tokens := strings.Split(string(line), " ")
+		if len(tokens) == 0 {
+			continue
+		}
+
+		switch tokens[0] {
+		case "next":
+			// "next" -> replay next message
+			// "next N" -> replay next N messages
+
+			if len(tokens) == 1 {
+				return 0
+			} else {
+				i, err := strconv.Atoi(tokens[1])
+				if err != nil {
+					fmt.Println("next takes an integer argument")
+				} else {
+					return i
+				}
+			}
+
+		case "back":
+			// "back" -> go back one message
+			// "back N" -> go back N messages
+
+			// NOTE: "back" is not supported in the state machine design,
+			// so we restart and replay up to
+
+			// ensure all new step events are regenerated as expected
+			newStepCh := subscribeToEvent(pb.cs.evsw, "replay-test", types.EventStringNewRoundStep(), 1)
+			if len(tokens) == 1 {
+				pb.replayReset(1, newStepCh)
+			} else {
+				i, err := strconv.Atoi(tokens[1])
+				if err != nil {
+					fmt.Println("back takes an integer argument")
+				} else if i > pb.count {
+					fmt.Printf("argument to back must not be larger than the current count (%d)\n", pb.count)
+				} else {
+					pb.replayReset(i, newStepCh)
+				}
+			}
+
+		case "rs":
+			// "rs" -> print entire round state
+			// "rs short" -> print height/round/step
+			// "rs <field>" -> print another field of the round state
+
+			rs := pb.cs.RoundState
+			if len(tokens) == 1 {
+				fmt.Println(rs)
+			} else {
+				switch tokens[1] {
+				case "short":
+					fmt.Printf("%v/%v/%v\n", rs.Height, rs.Round, rs.Step)
+				case "validators":
+					fmt.Println(rs.Validators)
+				case "proposal":
+					fmt.Println(rs.Proposal)
+				case "proposal_block":
+					fmt.Printf("%v %v\n", rs.ProposalBlockParts.StringShort(), rs.ProposalBlock.StringShort())
+				case "locked_round":
+					fmt.Println(rs.LockedRound)
+				case "locked_block":
+					fmt.Printf("%v %v\n", rs.LockedBlockParts.StringShort(), rs.LockedBlock.StringShort())
+				case "votes":
+					fmt.Println(rs.Votes.StringIndented("    "))
+
+				default:
+					fmt.Println("Unknown option", tokens[1])
+				}
+			}
+		case "n":
+			fmt.Println(pb.count)
+		}
+	}
+	return 0
+}
diff --git a/consensus/replay_test.go b/consensus/replay_test.go
new file mode 100644
index 00000000..2e93450a
--- /dev/null
+++ b/consensus/replay_test.go
@@ -0,0 +1,72 @@
+package consensus
+
+import (
+	"io/ioutil"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/tendermint/tendermint/types"
+)
+
+var testLog = `{"time":"2016-01-18T20:46:00.774Z","msg":[3,{"duration":982632969,"height":1,"round":0,"step":1}]}
+{"time":"2016-01-18T20:46:00.776Z","msg":[1,{"height":1,"round":0,"step":"RoundStepPropose"}]}
+{"time":"2016-01-18T20:46:00.776Z","msg":[2,{"msg":[17,{"Proposal":{"height":1,"round":0,"block_parts_header":{"total":1,"hash":"B6227255FF20758326B0B7DFF529F20E33E58F45"},"pol_round":-1,"signature":"A1803A1364F6398C154FE45D5649A89129039F18A0FE42B211BADFDF6E81EA53F48F83D3610DDD848C3A5284D3F09BDEB26FA1D856BDF70D48C507BF2453A70E"}}],"peer_key":""}]}
+{"time":"2016-01-18T20:46:00.777Z","msg":[2,{"msg":[19,{"Height":1,"Round":0,"Part":{"index":0,"bytes":"0101010F74656E6465726D696E745F746573740101142AA030B15DDFC000000000000000000000000000000114C4B01D3810579550997AC5641E759E20D99B51C10001000100","proof":{"aunts":[]}}}],"peer_key":""}]}
+{"time":"2016-01-18T20:46:00.781Z","msg":[1,{"height":1,"round":0,"step":"RoundStepPrevote"}]}
+{"time":"2016-01-18T20:46:00.781Z","msg":[2,{"msg":[20,{"ValidatorIndex":0,"Vote":{"height":1,"round":0,"type":1,"block_hash":"E05D1DB8DEC7CDA507A42C8FF208EE4317C663F6","block_parts_header":{"total":1,"hash":"B6227255FF20758326B0B7DFF529F20E33E58F45"},"signature":"88F5708C802BEE54EFBF438967FBC6C6EAAFC41258A85D92B9B055481175BE9FA71007B1AAF2BFBC3BF3CC0542DB48A9812324B7BBA7307446CCDBF029077F07"}}],"peer_key":""}]}
+{"time":"2016-01-18T20:46:00.786Z","msg":[1,{"height":1,"round":0,"step":"RoundStepPrecommit"}]}
+{"time":"2016-01-18T20:46:00.786Z","msg":[2,{"msg":[20,{"ValidatorIndex":0,"Vote":{"height":1,"round":0,"type":2,"block_hash":"E05D1DB8DEC7CDA507A42C8FF208EE4317C663F6","block_parts_header":{"total":1,"hash":"B6227255FF20758326B0B7DFF529F20E33E58F45"},"signature":"65B0C9D2A8C9919FC9B036F82C3F1818E706E8BC066A78D99D3316E4814AB06594841E387B323AA7773F926D253C1E4D4A0930F7A8C8AE1E838CA15C673B2B02"}}],"peer_key":""}]}
+`
+
+func TestReplayCatchup(t *testing.T) {
+	// write the needed wal to file
+	f, err := ioutil.TempFile(os.TempDir(), "replay_test_")
+	if err != nil {
+		t.Fatal(err)
+	}
+	name := f.Name()
+	_, err = f.WriteString(testLog)
+	if err != nil {
+		t.Fatal(err)
+	}
+	f.Close()
+
+	cs := fixedConsensusState()
+
+	// we've already precommitted on the first block
+	// without replay catchup we would be halted here forever
+	cs.privValidator.LastHeight = 1 // first block
+	cs.privValidator.LastStep = 3   // precommit
+
+	newBlockCh := subscribeToEvent(cs.evsw, "tester", types.EventStringNewBlock(), 0)
+
+	// start timeout and receive routines
+	cs.startRoutines(0)
+
+	// open wal and run catchup messages
+	openWAL(t, cs, name)
+	if err := cs.catchupReplay(cs.Height); err != nil {
+		t.Fatalf("Error on catchup replay %v", err)
+	}
+
+	cs.enterNewRound(cs.Height, cs.Round)
+
+	after := time.After(time.Second * 2)
+	select {
+	case <-newBlockCh:
+	case <-after:
+		t.Fatal("Timed out waiting for new block")
+	}
+
+}
+
+func openWAL(t *testing.T, cs *ConsensusState, file string) {
+	// open the wal
+	wal, err := NewWAL(file)
+	if err != nil {
+		t.Fatal(err)
+	}
+	wal.exists = true
+	cs.wal = wal
+}
diff --git a/consensus/state.go b/consensus/state.go
index 84d7fe2f..2fa3cd2c 100644
--- a/consensus/state.go
+++ b/consensus/state.go
@@ -19,7 +19,8 @@ import (
 )
 
 var (
-	timeoutPropose        = 3000 * time.Millisecond // Maximum duration of RoundStepPropose
+	timeoutPropose0       = 3000 * time.Millisecond // Wait this long for a proposal
+	timeoutProposeDelta   = 0500 * time.Millisecond // timeoutProposeN is timeoutPropose0 + timeoutProposeDelta*N
 	timeoutPrevote0       = 1000 * time.Millisecond // After any +2/3 prevotes received, wait this long for stragglers.
 	timeoutPrevoteDelta   = 0500 * time.Millisecond // timeoutPrevoteN is timeoutPrevote0 + timeoutPrevoteDelta*N
 	timeoutPrecommit0     = 1000 * time.Millisecond // After any +2/3 precommits received, wait this long for stragglers.
@@ -153,20 +154,20 @@ var (
 
 // msgs from the reactor which may update the state
 type msgInfo struct {
-	msg     ConsensusMessage
-	peerKey string
+	Msg     ConsensusMessage `json:"msg"`
+	PeerKey string           `json:"peer_key"`
 }
 
 // internally generated messages which may update the state
 type timeoutInfo struct {
-	duration time.Duration
-	height   int
-	round    int
-	step     RoundStepType
+	Duration time.Duration `json:"duration"`
+	Height   int           `json:"height"`
+	Round    int           `json:"round"`
+	Step     RoundStepType `json:"step"`
 }
 
 func (ti *timeoutInfo) String() string {
-	return fmt.Sprintf("%v ; %d/%d %v", ti.duration, ti.height, ti.round, ti.step)
+	return fmt.Sprintf("%v ; %d/%d %v", ti.Duration, ti.Height, ti.Round, ti.Step)
 }
 
 // Tracks consensus state across block heights and rounds.
@@ -190,6 +191,8 @@ type ConsensusState struct {
 
 	evsw *events.EventSwitch
 
+	wal *WAL
+
 	nSteps int // used for testing to limit the number of transitions the state makes
 }
 
@@ -248,14 +251,21 @@ func (cs *ConsensusState) SetPrivValidator(priv *types.PrivValidator) {
 }
 
 func (cs *ConsensusState) OnStart() error {
-	cs.BaseService.OnStart()
+	cs.QuitService.OnStart()
 
-	// first we schedule the round (no go routines)
-	// then we start the timeout and receive routines.
-	// tickChan is buffered so scheduleRound0 will finish.
-	// Then all further access to the RoundState is through the receiveRoutine
-	cs.scheduleRound0(cs.Height)
+	// start timeout and receive routines
 	cs.startRoutines(0)
+
+	// we may have lost some votes if the process crashed
+	// reload from consensus log to catchup
+	if err := cs.catchupReplay(cs.Height); err != nil {
+		log.Error("Error on catchup replay", "error", err.Error())
+		// let's go for it anyways, maybe we're fine
+	}
+
+	// schedule the first round!
+	cs.scheduleRound0(cs.Height)
+
 	return nil
 }
 
@@ -270,6 +280,18 @@ func (cs *ConsensusState) OnStop() {
 	cs.QuitService.OnStop()
 }
 
+// Open file to log all consensus messages and timeouts for deterministic accountability
+func (cs *ConsensusState) OpenWAL(file string) (err error) {
+	cs.mtx.Lock()
+	defer cs.mtx.Unlock()
+	wal, err := NewWAL(file)
+	if err != nil {
+		return err
+	}
+	cs.wal = wal
+	return nil
+}
+
 //------------------------------------------------------------
 // Public interface for passing messages into the consensus state,
 // possibly causing a state transition
@@ -372,8 +394,8 @@ func (cs *ConsensusState) reconstructLastCommit(state *sm.State) {
 	if state.LastBlockHeight == 0 {
 		return
 	}
-	lastPrecommits := types.NewVoteSet(state.LastBlockHeight, 0, types.VoteTypePrecommit, state.LastValidators)
 	seenValidation := cs.blockStore.LoadSeenValidation(state.LastBlockHeight)
+	lastPrecommits := types.NewVoteSet(state.LastBlockHeight, seenValidation.Round(), types.VoteTypePrecommit, state.LastValidators)
 	for idx, precommit := range seenValidation.Precommits {
 		if precommit == nil {
 			continue
@@ -455,10 +477,12 @@ func (cs *ConsensusState) updateToState(state *sm.State) {
 }
 
 func (cs *ConsensusState) newStep() {
+	rs := cs.RoundStateEvent()
+	cs.wal.Save(rs)
 	cs.nSteps += 1
 	// newStep is called by updateToStep in NewConsensusState before the evsw is set!
 	if cs.evsw != nil {
-		cs.evsw.FireEvent(types.EventStringNewRoundStep(), cs.RoundStateEvent())
+		cs.evsw.FireEvent(types.EventStringNewRoundStep(), rs)
 	}
 }
 
@@ -477,13 +501,13 @@ func (cs *ConsensusState) timeoutRoutine() {
 			log.Debug("Received tick", "old_ti", ti, "new_ti", newti)
 
 			// ignore tickers for old height/round/step
-			if newti.height < ti.height {
+			if newti.Height < ti.Height {
 				continue
-			} else if newti.height == ti.height {
-				if newti.round < ti.round {
+			} else if newti.Height == ti.Height {
+				if newti.Round < ti.Round {
 					continue
-				} else if newti.round == ti.round {
-					if ti.step > 0 && newti.step <= ti.step {
+				} else if newti.Round == ti.Round {
+					if ti.Step > 0 && newti.Step <= ti.Step {
 						continue
 					}
 				}
@@ -492,16 +516,16 @@ func (cs *ConsensusState) timeoutRoutine() {
 			ti = newti
 
 			// if the newti has duration == 0, we relay to the tockChan immediately (no timeout)
-			if ti.duration == time.Duration(0) {
+			if ti.Duration == time.Duration(0) {
 				go func(t timeoutInfo) { cs.tockChan <- t }(ti)
 				continue
 			}
 
-			log.Info("Scheduling timeout", "dur", ti.duration, "height", ti.height, "round", ti.round, "step", ti.step)
+			log.Debug("Scheduling timeout", "dur", ti.Duration, "height", ti.Height, "round", ti.Round, "step", ti.Step)
 			cs.timeoutTicker.Stop()
-			cs.timeoutTicker = time.NewTicker(ti.duration)
+			cs.timeoutTicker = time.NewTicker(ti.Duration)
 		case <-cs.timeoutTicker.C:
-			log.Info("Timed out", "dur", ti.duration, "height", ti.height, "round", ti.round, "step", ti.step)
+			log.Info("Timed out", "dur", ti.Duration, "height", ti.Height, "round", ti.Round, "step", ti.Step)
 			cs.timeoutTicker.Stop()
 			// go routine here gaurantees timeoutRoutine doesn't block.
 			// Determinism comes from playback in the receiveRoutine.
@@ -537,17 +561,24 @@ func (cs *ConsensusState) receiveRoutine(maxSteps int) {
 
 		select {
 		case mi = <-cs.peerMsgQueue:
+			cs.wal.Save(mi)
 			// handles proposals, block parts, votes
 			// may generate internal events (votes, complete proposals, 2/3 majorities)
 			cs.handleMsg(mi, rs)
 		case mi = <-cs.internalMsgQueue:
+			cs.wal.Save(mi)
 			// handles proposals, block parts, votes
 			cs.handleMsg(mi, rs)
 		case ti := <-cs.tockChan:
+			cs.wal.Save(ti)
 			// if the timeout is relevant to the rs
 			// go to the next step
 			cs.handleTimeout(ti, rs)
 		case <-cs.Quit:
+			// close wal now that we're done writing to it
+			if cs.wal != nil {
+				cs.wal.Close()
+			}
 			return
 		}
 	}
@@ -559,7 +590,7 @@ func (cs *ConsensusState) handleMsg(mi msgInfo, rs RoundState) {
 	defer cs.mtx.Unlock()
 
 	var err error
-	msg, peerKey := mi.msg, mi.peerKey
+	msg, peerKey := mi.Msg, mi.PeerKey
 	switch msg := msg.(type) {
 	case *ProposalMessage:
 		// will not cause transition.
@@ -592,10 +623,10 @@ func (cs *ConsensusState) handleMsg(mi msgInfo, rs RoundState) {
 }
 
 func (cs *ConsensusState) handleTimeout(ti timeoutInfo, rs RoundState) {
-	log.Debug("Received tock", "timeout", ti.duration, "height", ti.height, "round", ti.round, "step", ti.step)
+	log.Debug("Received tock", "timeout", ti.Duration, "height", ti.Height, "round", ti.Round, "step", ti.Step)
 
 	// timeouts must be for current height, round, step
-	if ti.height != rs.Height || ti.round < rs.Round || (ti.round == rs.Round && ti.step < rs.Step) {
+	if ti.Height != rs.Height || ti.Round < rs.Round || (ti.Round == rs.Round && ti.Step < rs.Step) {
 		log.Debug("Ignoring tock because we're ahead", "height", rs.Height, "round", rs.Round, "step", rs.Step)
 		return
 	}
@@ -604,22 +635,22 @@ func (cs *ConsensusState) handleTimeout(ti timeoutInfo, rs RoundState) {
 	cs.mtx.Lock()
 	defer cs.mtx.Unlock()
 
-	switch ti.step {
+	switch ti.Step {
 	case RoundStepNewHeight:
 		// NewRound event fired from enterNewRound.
-		// Do we want a timeout event too?
-		cs.enterNewRound(ti.height, 0)
+		// XXX: should we fire timeout here?
+		cs.enterNewRound(ti.Height, 0)
 	case RoundStepPropose:
 		cs.evsw.FireEvent(types.EventStringTimeoutPropose(), cs.RoundStateEvent())
-		cs.enterPrevote(ti.height, ti.round)
+		cs.enterPrevote(ti.Height, ti.Round)
 	case RoundStepPrevoteWait:
 		cs.evsw.FireEvent(types.EventStringTimeoutWait(), cs.RoundStateEvent())
-		cs.enterPrecommit(ti.height, ti.round)
+		cs.enterPrecommit(ti.Height, ti.Round)
 	case RoundStepPrecommitWait:
 		cs.evsw.FireEvent(types.EventStringTimeoutWait(), cs.RoundStateEvent())
-		cs.enterNewRound(ti.height, ti.round+1)
+		cs.enterNewRound(ti.Height, ti.Round+1)
 	default:
-		panic(Fmt("Invalid timeout step: %v", ti.step))
+		panic(Fmt("Invalid timeout step: %v", ti.Step))
 	}
 
 }
@@ -676,9 +707,6 @@ func (cs *ConsensusState) enterNewRound(height int, round int) {
 
 // Enter: from NewRound(height,round).
 func (cs *ConsensusState) enterPropose(height int, round int) {
-	//	cs.mtx.Lock()
-	//	cs.mtx.Unlock()
-
 	if cs.Height != height || round < cs.Round || (cs.Round == round && RoundStepPropose <= cs.Step) {
 		log.Debug(Fmt("enterPropose(%v/%v): Invalid args. Current step: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
 		return
@@ -699,7 +727,7 @@ func (cs *ConsensusState) enterPropose(height int, round int) {
 	}()
 
 	// This step times out after `timeoutPropose`
-	cs.scheduleTimeout(timeoutPropose, height, round, RoundStepPropose)
+	cs.scheduleTimeout(timeoutPropose0+timeoutProposeDelta*time.Duration(round), height, round, RoundStepPropose)
 
 	// Nothing more to do if we're not a validator
 	if cs.privValidator == nil {
@@ -826,8 +854,6 @@ func (cs *ConsensusState) createProposalBlock() (block *types.Block, blockParts
 // Prevote for LockedBlock if we're locked, or ProposalBlock if valid.
 // Otherwise vote nil.
 func (cs *ConsensusState) enterPrevote(height int, round int) {
-	//cs.mtx.Lock()
-	//defer cs.mtx.Unlock()
 	if cs.Height != height || round < cs.Round || (cs.Round == round && RoundStepPrevote <= cs.Step) {
 		log.Debug(Fmt("enterPrevote(%v/%v): Invalid args. Current step: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
 		return
@@ -891,8 +917,6 @@ func (cs *ConsensusState) doPrevote(height int, round int) {
 
 // Enter: any +2/3 prevotes at next round.
 func (cs *ConsensusState) enterPrevoteWait(height int, round int) {
-	//cs.mtx.Lock()
-	//defer cs.mtx.Unlock()
 	if cs.Height != height || round < cs.Round || (cs.Round == round && RoundStepPrevoteWait <= cs.Step) {
 		log.Debug(Fmt("enterPrevoteWait(%v/%v): Invalid args. Current step: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
 		return
@@ -919,8 +943,6 @@ func (cs *ConsensusState) enterPrevoteWait(height int, round int) {
 // else, unlock an existing lock and precommit nil if +2/3 of prevotes were nil,
 // else, precommit nil otherwise.
 func (cs *ConsensusState) enterPrecommit(height int, round int) {
-	//cs.mtx.Lock()
-	//	defer cs.mtx.Unlock()
 	if cs.Height != height || round < cs.Round || (cs.Round == round && RoundStepPrecommit <= cs.Step) {
 		log.Debug(Fmt("enterPrecommit(%v/%v): Invalid args. Current step: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
 		return
@@ -1016,8 +1038,6 @@ func (cs *ConsensusState) enterPrecommit(height int, round int) {
 
 // Enter: any +2/3 precommits for next round.
 func (cs *ConsensusState) enterPrecommitWait(height int, round int) {
-	//cs.mtx.Lock()
-	//defer cs.mtx.Unlock()
 	if cs.Height != height || round < cs.Round || (cs.Round == round && RoundStepPrecommitWait <= cs.Step) {
 		log.Debug(Fmt("enterPrecommitWait(%v/%v): Invalid args. Current step: %v/%v/%v", height, round, cs.Height, cs.Round, cs.Step))
 		return
@@ -1040,8 +1060,6 @@ func (cs *ConsensusState) enterPrecommitWait(height int, round int) {
 
 // Enter: +2/3 precommits for block
 func (cs *ConsensusState) enterCommit(height int, commitRound int) {
-	//cs.mtx.Lock()
-	//defer cs.mtx.Unlock()
 	if cs.Height != height || RoundStepCommit <= cs.Step {
 		log.Debug(Fmt("enterCommit(%v/%v): Invalid args. Current step: %v/%v/%v", height, commitRound, cs.Height, cs.Round, cs.Step))
 		return
@@ -1107,9 +1125,6 @@ func (cs *ConsensusState) tryFinalizeCommit(height int) {
 
 // Increment height and goto RoundStepNewHeight
 func (cs *ConsensusState) finalizeCommit(height int) {
-	//cs.mtx.Lock()
-	//defer cs.mtx.Unlock()
-
 	if cs.Height != height || cs.Step != RoundStepCommit {
 		log.Debug(Fmt("finalizeCommit(%v): Invalid args. Current step: %v/%v/%v", height, cs.Height, cs.Round, cs.Step))
 		return
@@ -1189,9 +1204,6 @@ func (cs *ConsensusState) finalizeCommit(height int) {
 //-----------------------------------------------------------------------------
 
 func (cs *ConsensusState) setProposal(proposal *types.Proposal) error {
-	//cs.mtx.Lock()
-	//defer cs.mtx.Unlock()
-
 	// Already have one
 	if cs.Proposal != nil {
 		return nil
@@ -1226,9 +1238,6 @@ func (cs *ConsensusState) setProposal(proposal *types.Proposal) error {
 // NOTE: block is not necessarily valid.
 // This can trigger us to go into enterPrevote asynchronously (before we timeout of propose) or to attempt to commit
 func (cs *ConsensusState) addProposalBlockPart(height int, part *types.Part) (added bool, err error) {
-	//cs.mtx.Lock()
-	//defer cs.mtx.Unlock()
-
 	// Blocks might be reused, so round mismatch is OK
 	if cs.Height != height {
 		return false, nil
@@ -1248,7 +1257,8 @@ func (cs *ConsensusState) addProposalBlockPart(height int, part *types.Part) (ad
 		var n int
 		var err error
 		cs.ProposalBlock = wire.ReadBinary(&types.Block{}, cs.ProposalBlockParts.GetReader(), types.MaxBlockSize, &n, &err).(*types.Block)
-		log.Info("Received complete proposal", "height", cs.ProposalBlock.Height, "hash", cs.ProposalBlock.Hash())
+		// NOTE: it's possible to receive complete proposal blocks for future rounds without having the proposal
+		log.Info("Received complete proposal block", "height", cs.ProposalBlock.Height, "hash", cs.ProposalBlock.Hash())
 		if cs.Step == RoundStepPropose && cs.isProposalComplete() {
 			// Move onto the next step
 			cs.enterPrevote(height, cs.Round)
@@ -1305,7 +1315,7 @@ func (cs *ConsensusState) addVote(valIndex int, vote *types.Vote, peerKey string
 		added, address, err = cs.LastCommit.AddByIndex(valIndex, vote)
 		if added {
 			log.Info(Fmt("Added to lastPrecommits: %v", cs.LastCommit.StringShort()))
-			cs.evsw.FireEvent(types.EventStringVote(), &types.EventDataVote{valIndex, address, vote})
+			cs.evsw.FireEvent(types.EventStringVote(), types.EventDataVote{valIndex, address, vote})
 
 		}
 		return
@@ -1316,7 +1326,7 @@ func (cs *ConsensusState) addVote(valIndex int, vote *types.Vote, peerKey string
 		height := cs.Height
 		added, address, err = cs.Votes.AddByIndex(valIndex, vote, peerKey)
 		if added {
-			cs.evsw.FireEvent(types.EventStringVote(), &types.EventDataVote{valIndex, address, vote})
+			cs.evsw.FireEvent(types.EventStringVote(), types.EventDataVote{valIndex, address, vote})
 
 			switch vote.Type {
 			case types.VoteTypePrevote:
diff --git a/consensus/state_test.go b/consensus/state_test.go
index beaafd49..1def6ae8 100644
--- a/consensus/state_test.go
+++ b/consensus/state_test.go
@@ -46,11 +46,12 @@ x * TestHalt1 - if we see +2/3 precommits after timing out into new round, we sh
 
 func init() {
 	fmt.Println("")
-	timeoutPropose = 500 * time.Millisecond
+	timeoutPropose0 = 100 * time.Millisecond
+	timeoutProposeDelta = 1 * time.Millisecond
 }
 
 func TestProposerSelection0(t *testing.T) {
-	cs1, vss := simpleConsensusState(4)
+	cs1, vss := randConsensusState(4)
 	height, round := cs1.Height, cs1.Round
 
 	newRoundCh := subscribeToEvent(cs1.evsw, "tester", types.EventStringNewRound(), 1)
@@ -84,7 +85,7 @@ func TestProposerSelection0(t *testing.T) {
 
 // Now let's do it all again, but starting from round 2 instead of 0
 func TestProposerSelection2(t *testing.T) {
-	cs1, vss := simpleConsensusState(4) // test needs more work for more than 3 validators
+	cs1, vss := randConsensusState(4) // test needs more work for more than 3 validators
 
 	newRoundCh := subscribeToEvent(cs1.evsw, "tester", types.EventStringNewRound(), 1)
 
@@ -113,7 +114,7 @@ func TestProposerSelection2(t *testing.T) {
 
 // a non-validator should timeout into the prevote round
 func TestEnterProposeNoPrivValidator(t *testing.T) {
-	cs, _ := simpleConsensusState(1)
+	cs, _ := randConsensusState(1)
 	cs.SetPrivValidator(nil)
 	height, round := cs.Height, cs.Round
 
@@ -123,7 +124,7 @@ func TestEnterProposeNoPrivValidator(t *testing.T) {
 	startTestRound(cs, height, round)
 
 	// if we're not a validator, EnterPropose should timeout
-	ticker := time.NewTicker(timeoutPropose * 2)
+	ticker := time.NewTicker(timeoutPropose0 * 2)
 	select {
 	case <-timeoutCh:
 	case <-ticker.C:
@@ -138,7 +139,7 @@ func TestEnterProposeNoPrivValidator(t *testing.T) {
 
 // a validator should not timeout of the prevote round (TODO: unless the block is really big!)
 func TestEnterProposeYesPrivValidator(t *testing.T) {
-	cs, _ := simpleConsensusState(1)
+	cs, _ := randConsensusState(1)
 	height, round := cs.Height, cs.Round
 
 	// Listen for propose timeout event
@@ -164,7 +165,7 @@ func TestEnterProposeYesPrivValidator(t *testing.T) {
 	}
 
 	// if we're a validator, enterPropose should not timeout
-	ticker := time.NewTicker(timeoutPropose * 2)
+	ticker := time.NewTicker(timeoutPropose0 * 2)
 	select {
 	case <-timeoutCh:
 		t.Fatal("Expected EnterPropose not to timeout")
@@ -174,7 +175,7 @@ func TestEnterProposeYesPrivValidator(t *testing.T) {
 }
 
 func TestBadProposal(t *testing.T) {
-	cs1, vss := simpleConsensusState(2)
+	cs1, vss := randConsensusState(2)
 	height, round := cs1.Height, cs1.Round
 	cs2 := vss[1]
 
@@ -230,7 +231,7 @@ func TestBadProposal(t *testing.T) {
 
 // propose, prevote, and precommit a block
 func TestFullRound1(t *testing.T) {
-	cs, vss := simpleConsensusState(1)
+	cs, vss := randConsensusState(1)
 	height, round := cs.Height, cs.Round
 
 	voteCh := subscribeToEvent(cs.evsw, "tester", types.EventStringVote(), 1)
@@ -258,7 +259,7 @@ func TestFullRound1(t *testing.T) {
 
 // nil is proposed, so prevote and precommit nil
 func TestFullRoundNil(t *testing.T) {
-	cs, vss := simpleConsensusState(1)
+	cs, vss := randConsensusState(1)
 	height, round := cs.Height, cs.Round
 
 	voteCh := subscribeToEvent(cs.evsw, "tester", types.EventStringVote(), 1)
@@ -276,7 +277,7 @@ func TestFullRoundNil(t *testing.T) {
 // run through propose, prevote, precommit commit with two validators
 // where the first validator has to wait for votes from the second
 func TestFullRound2(t *testing.T) {
-	cs1, vss := simpleConsensusState(2)
+	cs1, vss := randConsensusState(2)
 	cs2 := vss[1]
 	height, round := cs1.Height, cs1.Round
 
@@ -317,7 +318,7 @@ func TestFullRound2(t *testing.T) {
 // two validators, 4 rounds.
 // two vals take turns proposing. val1 locks on first one, precommits nil on everything else
 func TestLockNoPOL(t *testing.T) {
-	cs1, vss := simpleConsensusState(2)
+	cs1, vss := randConsensusState(2)
 	cs2 := vss[1]
 	height := cs1.Height
 
@@ -480,7 +481,7 @@ func TestLockNoPOL(t *testing.T) {
 
 // 4 vals, one precommits, other 3 polka at next round, so we unlock and precomit the polka
 func TestLockPOLRelock(t *testing.T) {
-	cs1, vss := simpleConsensusState(4)
+	cs1, vss := randConsensusState(4)
 	cs2, cs3, cs4 := vss[1], vss[2], vss[3]
 
 	timeoutProposeCh := subscribeToEvent(cs1.evsw, "tester", types.EventStringTimeoutPropose(), 1)
@@ -588,7 +589,7 @@ func TestLockPOLRelock(t *testing.T) {
 
 // 4 vals, one precommits, other 3 polka at next round, so we unlock and precomit the polka
 func TestLockPOLUnlock(t *testing.T) {
-	cs1, vss := simpleConsensusState(4)
+	cs1, vss := randConsensusState(4)
 	cs2, cs3, cs4 := vss[1], vss[2], vss[3]
 
 	proposalCh := subscribeToEvent(cs1.evsw, "tester", types.EventStringCompleteProposal(), 1)
@@ -679,7 +680,7 @@ func TestLockPOLUnlock(t *testing.T) {
 // then a polka at round 2 that we lock on
 // then we see the polka from round 1 but shouldn't unlock
 func TestLockPOLSafety1(t *testing.T) {
-	cs1, vss := simpleConsensusState(4)
+	cs1, vss := randConsensusState(4)
 	cs2, cs3, cs4 := vss[1], vss[2], vss[3]
 
 	proposalCh := subscribeToEvent(cs1.evsw, "tester", types.EventStringCompleteProposal(), 1)
@@ -798,7 +799,7 @@ func TestLockPOLSafety1(t *testing.T) {
 // What we want:
 // dont see P0, lock on P1 at R1, dont unlock using P0 at R2
 func TestLockPOLSafety2(t *testing.T) {
-	cs1, vss := simpleConsensusState(4)
+	cs1, vss := randConsensusState(4)
 	cs2, cs3, cs4 := vss[1], vss[2], vss[3]
 
 	proposalCh := subscribeToEvent(cs1.evsw, "tester", types.EventStringCompleteProposal(), 1)
@@ -888,7 +889,7 @@ func TestLockPOLSafety2(t *testing.T) {
 
 /*
 func TestSlashingPrevotes(t *testing.T) {
-	cs1, vss := simpleConsensusState(2)
+	cs1, vss := randConsensusState(2)
 	cs2 := vss[1]
 
 
@@ -923,7 +924,7 @@ func TestSlashingPrevotes(t *testing.T) {
 }
 
 func TestSlashingPrecommits(t *testing.T) {
-	cs1, vss := simpleConsensusState(2)
+	cs1, vss := randConsensusState(2)
 	cs2 := vss[1]
 
 
@@ -968,7 +969,7 @@ func TestSlashingPrecommits(t *testing.T) {
 // 4 vals.
 // we receive a final precommit after going into next round, but others might have gone to commit already!
 func TestHalt1(t *testing.T) {
-	cs1, vss := simpleConsensusState(4)
+	cs1, vss := randConsensusState(4)
 	cs2, cs3, cs4 := vss[1], vss[2], vss[3]
 
 	proposalCh := subscribeToEvent(cs1.evsw, "tester", types.EventStringCompleteProposal(), 1)
diff --git a/consensus/wal.go b/consensus/wal.go
new file mode 100644
index 00000000..46f7a9df
--- /dev/null
+++ b/consensus/wal.go
@@ -0,0 +1,117 @@
+package consensus
+
+import (
+	"bufio"
+	"os"
+	"time"
+
+	. "github.com/tendermint/go-common"
+	"github.com/tendermint/go-wire"
+	"github.com/tendermint/tendermint/types"
+)
+
+//--------------------------------------------------------
+// types and functions for savings consensus messages
+
+type ConsensusLogMessage struct {
+	Time time.Time                    `json:"time"`
+	Msg  ConsensusLogMessageInterface `json:"msg"`
+}
+
+type ConsensusLogMessageInterface interface{}
+
+var _ = wire.RegisterInterface(
+	struct{ ConsensusLogMessageInterface }{},
+	wire.ConcreteType{types.EventDataRoundState{}, 0x01},
+	wire.ConcreteType{msgInfo{}, 0x02},
+	wire.ConcreteType{timeoutInfo{}, 0x03},
+)
+
+//--------------------------------------------------------
+// Simple write-ahead logger
+
+// Write ahead logger writes msgs to disk before they are processed.
+// Can be used for crash-recovery and deterministic replay
+// TODO: currently the wal is overwritten during replay catchup
+//   give it a mode so it's either reading or appending - must read to end to start appending again
+type WAL struct {
+	fp     *os.File
+	exists bool // if the file already existed (restarted process)
+}
+
+func NewWAL(file string) (*WAL, error) {
+	var walExists bool
+	if _, err := os.Stat(file); err == nil {
+		walExists = true
+	}
+	fp, err := os.OpenFile(file, os.O_RDWR|os.O_APPEND|os.O_CREATE, 0600)
+	if err != nil {
+		return nil, err
+	}
+	return &WAL{
+		fp:     fp,
+		exists: walExists,
+	}, nil
+}
+
+// called in newStep and for each pass in receiveRoutine
+func (wal *WAL) Save(msg ConsensusLogMessageInterface) {
+	if wal != nil {
+		var n int
+		var err error
+		wire.WriteJSON(ConsensusLogMessage{time.Now(), msg}, wal.fp, &n, &err)
+		wire.WriteTo([]byte("\n"), wal.fp, &n, &err) // one message per line
+		if err != nil {
+			PanicQ(Fmt("Error writing msg to consensus wal. Error: %v \n\nMessage: %v", err, msg))
+		}
+	}
+}
+
+// Must not be called concurrently.
+func (wal *WAL) Close() {
+	if wal != nil {
+		wal.fp.Close()
+	}
+}
+
+func (wal *WAL) SeekFromEnd(found func([]byte) bool) (nLines int, err error) {
+	var current int64
+	// start at the end
+	current, err = wal.fp.Seek(0, 2)
+	if err != nil {
+		return
+	}
+
+	// backup until we find the the right line
+	// current is how far we are from the beginning
+	for {
+		current -= 1
+		if current < 0 {
+			wal.fp.Seek(0, 0) // back to beginning
+			return
+		}
+		// backup one and read a new byte
+		if _, err = wal.fp.Seek(current, 0); err != nil {
+			return
+		}
+		b := make([]byte, 1)
+		if _, err = wal.fp.Read(b); err != nil {
+			return
+		}
+		if b[0] == '\n' || len(b) == 0 {
+			nLines += 1
+			// read a full line
+			reader := bufio.NewReader(wal.fp)
+			lineBytes, _ := reader.ReadBytes('\n')
+			if len(lineBytes) == 0 {
+				continue
+			}
+
+			if found(lineBytes) {
+				wal.fp.Seek(0, 1) // (?)
+				wal.fp.Seek(current, 0)
+				return
+			}
+		}
+	}
+}
diff --git a/consensus/wal_test.go b/consensus/wal_test.go
new file mode 100644
index 00000000..8348ca24
--- /dev/null
+++ b/consensus/wal_test.go
@@ -0,0 +1,76 @@
+package consensus
+
+import (
+	"io/ioutil"
+	"os"
+	"path"
+	"strings"
+	"testing"
+)
+
+var testTxt = `{"time":"2016-01-16T04:42:00.390Z","msg":[1,{"height":28219,"round":0,"step":"RoundStepPrevote"}]}
+{"time":"2016-01-16T04:42:00.390Z","msg":[2,{"msg":[20,{"ValidatorIndex":0,"Vote":{"height":28219,"round":0,"type":1,"block_hash":"67F9689F15BEC30BF311FB4C0C80C5E661AA44E0","block_parts_header":{"total":1,"hash":"DFFD4409A1E273ED61AC27CAF975F446020D5676"},"signature":"4CC6845A128E723A299B470CCBB2A158612AA51321447F6492F3DA57D135C27FCF4124B3B19446A248252BDA45B152819C76AAA5FD35E1C07091885CE6955E05"}}],"peer_key":""}]}
+{"time":"2016-01-16T04:42:00.392Z","msg":[1,{"height":28219,"round":0,"step":"RoundStepPrecommit"}]}
+{"time":"2016-01-16T04:42:00.392Z","msg":[2,{"msg":[20,{"ValidatorIndex":0,"Vote":{"height":28219,"round":0,"type":2,"block_hash":"67F9689F15BEC30BF311FB4C0C80C5E661AA44E0","block_parts_header":{"total":1,"hash":"DFFD4409A1E273ED61AC27CAF975F446020D5676"},"signature":"1B9924E010F47E0817695DFE462C531196E5A12632434DE12180BBA3EFDAD6B3960FDB9357AFF085EB61729A7D4A6AD8408555D7569C87D9028F280192FD4E05"}}],"peer_key":""}]}
+{"time":"2016-01-16T04:42:00.393Z","msg":[1,{"height":28219,"round":0,"step":"RoundStepCommit"}]}
+{"time":"2016-01-16T04:42:00.395Z","msg":[1,{"height":28220,"round":0,"step":"RoundStepNewHeight"}]}`
+
+func TestSeek(t *testing.T) {
+	f, err := ioutil.TempFile(os.TempDir(), "seek_test_")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	stat, _ := f.Stat()
+	name := stat.Name()
+
+	_, err = f.WriteString(testTxt)
+	if err != nil {
+		t.Fatal(err)
+	}
+	f.Close()
+
+	wal, err := NewWAL(path.Join(os.TempDir(), name))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	keyWord := "Precommit"
+	n, err := wal.SeekFromEnd(func(b []byte) bool {
+		if strings.Contains(string(b), keyWord) {
+			return true
+		}
+		return false
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// confirm n
+	spl := strings.Split(testTxt, "\n")
+	var i int
+	var s string
+	for i, s = range spl {
+		if strings.Contains(s, keyWord) {
+			break
+		}
+	}
+	// n is lines from the end.
+	spl = spl[i:]
+	if n != len(spl) {
+		t.Fatalf("Wrong nLines. Got %d, expected %d", n, len(spl))
+	}
+
+	b, err := ioutil.ReadAll(wal.fp)
+	if err != nil {
+		t.Fatal(err)
+	}
+	// first char is a \n
+	spl2 := strings.Split(strings.Trim(string(b), "\n"), "\n")
+	for i, s := range spl {
+		if s != spl2[i] {
+			t.Fatalf("Mismatch. Got %s, expected %s", spl2[i], s)
+		}
+	}
+
+}
diff --git a/node/node.go b/node/node.go
index bda20084..3d02589c 100644
--- a/node/node.go
+++ b/node/node.go
@@ -84,6 +84,12 @@ func NewNode(privValidator *types.PrivValidator) *Node {
 		consensusReactor.SetPrivValidator(privValidator)
 	}
 
+	// deterministic accountability
+	err = consensusState.OpenWAL(config.GetString("cswal"))
+	if err != nil {
+		log.Error("Failed to open cswal", "error", err.Error())
+	}
+
 	// Make p2p network switch
 	sw := p2p.NewSwitch()
 	sw.AddReactor("MEMPOOL", mempoolReactor)
@@ -219,6 +225,49 @@ func makeNodeInfo(sw *p2p.Switch, privKey crypto.PrivKeyEd25519) *p2p.NodeInfo {
 	return nodeInfo
 }
 
+// Get a connection to the proxyAppConn addr.
+// Check the current hash, and panic if it doesn't match.
+func getProxyApp(addr string, hash []byte) (proxyAppConn proxy.AppConn) {
+	// use local app (for testing)
+	if addr == "local" {
+		app := example.NewCounterApplication(true)
+		mtx := new(sync.Mutex)
+		proxyAppConn = proxy.NewLocalAppConn(mtx, app)
+	} else {
+		proxyConn, err := Connect(addr)
+		if err != nil {
+			Exit(Fmt("Failed to connect to proxy for mempool: %v", err))
+		}
+		remoteApp := proxy.NewRemoteAppConn(proxyConn, 1024)
+		remoteApp.Start()
+
+		proxyAppConn = remoteApp
+	}
+
+	// Check the hash
+	currentHash, err := proxyAppConn.GetHashSync()
+	if err != nil {
+		PanicCrisis(Fmt("Error in getting proxyAppConn hash: %v", err))
+	}
+	if !bytes.Equal(hash, currentHash) {
+		PanicCrisis(Fmt("ProxyApp hash does not match.  Expected %X, got %X", hash, currentHash))
+	}
+
+	return proxyAppConn
+}
+
+// Load the most recent state from "state" db,
+// or create a new one (and save) from genesis.
+func getState() *sm.State {
+	stateDB := dbm.GetDB("state")
+	state := sm.LoadState(stateDB)
+	if state == nil {
+		state = sm.MakeGenesisStateFromFile(stateDB, config.GetString("genesis_file"))
+		state.Save()
+	}
+	return state
+}
+
 //------------------------------------------------------------------------------
 
 // Users wishing to use an external signer for their validators
@@ -283,45 +332,65 @@ func RunNode() {
 	})
 }
 
-// Load the most recent state from "state" db,
-// or create a new one (and save) from genesis.
-func getState() *sm.State {
+//------------------------------------------------------------------------------
+// replay
+
+// convenience for replay mode
+func newConsensusState() *consensus.ConsensusState {
+	// Get BlockStore
+	blockStoreDB := dbm.GetDB("blockstore")
+	blockStore := bc.NewBlockStore(blockStoreDB)
+
+	// Get State
 	stateDB := dbm.GetDB("state")
-	state := sm.LoadState(stateDB)
-	if state == nil {
-		state = sm.MakeGenesisStateFromFile(stateDB, config.GetString("genesis_file"))
-		state.Save()
-	}
-	return state
-}
+	state := sm.MakeGenesisStateFromFile(stateDB, config.GetString("genesis_file"))
 
-// Get a connection to the proxyAppConn addr.
-// Check the current hash, and panic if it doesn't match.
-func getProxyApp(addr string, hash []byte) (proxyAppConn proxy.AppConn) {
-	// use local app (for testing)
-	if addr == "local" {
-		app := example.NewCounterApplication(true)
-		mtx := new(sync.Mutex)
-		proxyAppConn = proxy.NewLocalAppConn(mtx, app)
-	} else {
-		proxyConn, err := Connect(addr)
-		if err != nil {
-			Exit(Fmt("Failed to connect to proxy for mempool: %v", err))
-		}
-		remoteApp := proxy.NewRemoteAppConn(proxyConn, 1024)
-		remoteApp.Start()
+	// Create two proxyAppConn connections,
+	// one for the consensus and one for the mempool.
+	proxyAddr := config.GetString("proxy_app")
+	proxyAppConnMempool := getProxyApp(proxyAddr, state.AppHash)
+	proxyAppConnConsensus := getProxyApp(proxyAddr, state.AppHash)
 
-		proxyAppConn = remoteApp
-	}
+	// add the chainid to the global config
+	config.Set("chain_id", state.ChainID)
 
-	// Check the hash
-	currentHash, err := proxyAppConn.GetHashSync()
+	// Make event switch
+	eventSwitch := events.NewEventSwitch()
+	_, err := eventSwitch.Start()
 	if err != nil {
-		PanicCrisis(Fmt("Error in getting proxyAppConn hash: %v", err))
-	}
-	if !bytes.Equal(hash, currentHash) {
-		PanicCrisis(Fmt("ProxyApp hash does not match.  Expected %X, got %X", hash, currentHash))
+		Exit(Fmt("Failed to start event switch: %v", err))
 	}
 
-	return proxyAppConn
+	mempool := mempl.NewMempool(proxyAppConnMempool)
+
+	consensusState := consensus.NewConsensusState(state.Copy(), proxyAppConnConsensus, blockStore, mempool)
+	consensusState.SetEventSwitch(eventSwitch)
+	return consensusState
+}
+
+func RunReplayConsole() {
+	walFile := config.GetString("cswal")
+	if walFile == "" {
+		Exit("cswal file name not set in tendermint config")
+	}
+
+	consensusState := newConsensusState()
+
+	if err := consensusState.ReplayConsole(walFile); err != nil {
+		Exit(Fmt("Error during consensus replay: %v", err))
+	}
+}
+
+func RunReplay() {
+	walFile := config.GetString("cswal")
+	if walFile == "" {
+		Exit("cswal file name not set in tendermint config")
+	}
+
+	consensusState := newConsensusState()
+
+	if err := consensusState.ReplayMessages(walFile); err != nil {
+		Exit(Fmt("Error during consensus replay: %v", err))
+	}
+	log.Notice("Replay run successfully")
 }
diff --git a/types/events.go b/types/events.go
index a316cfc5..7bcd2ea2 100644
--- a/types/events.go
+++ b/types/events.go
@@ -75,6 +75,7 @@ type EventDataApp struct {
 	Data []byte `json:"bytes"`
 }
 
+// NOTE: This goes into the replay WAL
 type EventDataRoundState struct {
 	Height int    `json:"height"`
 	Round  int    `json:"round"`