diff --git a/binary/codec.go b/binary/codec.go
index 954a50cf..79799d9f 100644
--- a/binary/codec.go
+++ b/binary/codec.go
@@ -119,7 +119,7 @@ func BasicCodecDecoder(r Unreader, n *int64, err *error) (o interface{}) {
 		o = ReadTime(r, n, err)
 	default:
 		if *err != nil {
-			panic(err)
+			panic(*err)
 		} else {
 			panic(fmt.Sprintf("Unsupported type byte: %X", type_))
 		}
diff --git a/binary/log.go b/binary/log.go
index 7dc9b319..28586125 100644
--- a/binary/log.go
+++ b/binary/log.go
@@ -11,6 +11,7 @@ func init() {
 	log.SetHandler(
 		log15.LvlFilterHandler(
 			log15.LvlWarn,
+			//log15.LvlDebug,
 			logger.RootHandler(),
 		),
 	)
diff --git a/block/tx.go b/block/tx.go
index 2a5ca034..3a841a39 100644
--- a/block/tx.go
+++ b/block/tx.go
@@ -15,7 +15,6 @@ var (
 	ErrTxInsufficientFunds = errors.New("Error insufficient funds")
 	ErrTxUnknownPubKey     = errors.New("Error unknown pubkey")
 	ErrTxInvalidPubKey     = errors.New("Error invalid pubkey")
-	ErrTxRedeclaredPubKey  = errors.New("Error redeclared pubkey")
 	ErrTxInvalidSignature  = errors.New("Error invalid signature")
 	ErrTxInvalidSequence   = errors.New("Error invalid sequence")
 )
diff --git a/consensus/state.go b/consensus/state.go
index c26eca06..ac670001 100644
--- a/consensus/state.go
+++ b/consensus/state.go
@@ -646,6 +646,7 @@ func (cs *ConsensusState) RunActionPropose(height uint, round uint) {
 	err := cs.PrivValidator.SignProposal(proposal)
 	if err == nil {
 		log.Info("Signed and set proposal", "height", cs.Height, "round", cs.Round, "proposal", proposal)
+		log.Debug(Fmt("Signed and set proposal block: %v", block))
 		// Set fields
 		cs.Proposal = proposal
 		cs.ProposalBlock = block
diff --git a/db/db.go b/db/db.go
index 241a0f42..afdea3da 100644
--- a/db/db.go
+++ b/db/db.go
@@ -13,6 +13,9 @@ type DB interface {
 	SetSync([]byte, []byte)
 	Delete([]byte)
 	DeleteSync([]byte)
+
+	// For debugging
+	Print()
 }
 
 //-----------------------------------------------------------------------------
diff --git a/mempool/mempool.go b/mempool/mempool.go
index 3c7abb4d..37dc8233 100644
--- a/mempool/mempool.go
+++ b/mempool/mempool.go
@@ -34,8 +34,10 @@ func (mem *Mempool) AddTx(tx Tx) (err error) {
 	defer mem.mtx.Unlock()
 	err = mem.state.ExecTx(tx)
 	if err != nil {
+		log.Debug("AddTx() error", "tx", tx, "error", err)
 		return err
 	} else {
+		log.Debug("AddTx() success", "tx", tx)
 		mem.txs = append(mem.txs, tx)
 		return nil
 	}
@@ -44,6 +46,7 @@ func (mem *Mempool) AddTx(tx Tx) (err error) {
 func (mem *Mempool) GetProposalTxs() []Tx {
 	mem.mtx.Lock()
 	defer mem.mtx.Unlock()
+	log.Debug("GetProposalTxs:", "txs", mem.txs)
 	return mem.txs
 }
 
@@ -68,8 +71,10 @@ func (mem *Mempool) ResetForBlockAndState(block *Block, state *state.State) {
 	for _, tx := range mem.txs {
 		txHash := BinarySha256(tx)
 		if _, ok := blockTxsMap[string(txHash)]; ok {
+			log.Debug("Filter out, already committed", "tx", tx, "txHash", txHash)
 			continue
 		} else {
+			log.Debug("Filter in, still new", "tx", tx, "txHash", txHash)
 			txs = append(txs, tx)
 		}
 	}
@@ -78,13 +83,16 @@ func (mem *Mempool) ResetForBlockAndState(block *Block, state *state.State) {
 	validTxs := []Tx{}
 	for _, tx := range txs {
 		err := mem.state.ExecTx(tx)
-		if err != nil {
+		if err == nil {
+			log.Debug("Filter in, valid", "tx", tx)
 			validTxs = append(validTxs, tx)
 		} else {
 			// tx is no longer valid.
+			log.Debug("Filter out, no longer valid", "tx", tx, "error", err)
 		}
 	}
 
 	// We're done!
+	log.Debug("New txs", "txs", validTxs, "oldTxs", mem.txs)
 	mem.txs = validTxs
 }
diff --git a/merkle/iavl_node.go b/merkle/iavl_node.go
index 3a1ea689..8ffc719d 100644
--- a/merkle/iavl_node.go
+++ b/merkle/iavl_node.go
@@ -67,7 +67,7 @@ func (node *IAVLNode) _copy() *IAVLNode {
 		leftNode:  node.leftNode,
 		rightHash: node.rightHash,
 		rightNode: node.rightNode,
-		persisted: node.persisted,
+		persisted: false, // Going to be mutated, so it can't already be persisted.
 	}
 }
 
diff --git a/merkle/iavl_tree.go b/merkle/iavl_tree.go
index f9c19ae4..d4203112 100644
--- a/merkle/iavl_tree.go
+++ b/merkle/iavl_tree.go
@@ -6,6 +6,7 @@ import (
 	"sync"
 
 	. "github.com/tendermint/tendermint/binary"
+	. "github.com/tendermint/tendermint/common"
 	db_ "github.com/tendermint/tendermint/db"
 )
 
@@ -205,12 +206,16 @@ func (ndb *nodeDB) GetNode(t *IAVLTree, hash []byte) *IAVLNode {
 	} else {
 		// Doesn't exist, load.
 		buf := ndb.db.Get(hash)
+		if len(buf) == 0 {
+			ndb.db.(*db_.LevelDB).Print()
+			panic(Fmt("Value missing for key %X", hash))
+		}
 		r := bytes.NewReader(buf)
 		var n int64
 		var err error
 		node := ReadIAVLNode(t, r, &n, &err)
 		if err != nil {
-			panic(err)
+			panic(Fmt("Error reading IAVLNode. bytes: %X  error: %v", buf, err))
 		}
 		node.persisted = true
 		ndb.cacheNode(node)
diff --git a/rpc/account.go b/rpc/account.go
new file mode 100644
index 00000000..4c07bf3b
--- /dev/null
+++ b/rpc/account.go
@@ -0,0 +1,56 @@
+package rpc
+
+import (
+	"net/http"
+
+	"github.com/tendermint/tendermint/account"
+	"github.com/tendermint/tendermint/binary"
+	"github.com/tendermint/tendermint/block"
+	. "github.com/tendermint/tendermint/common"
+)
+
+type GenPrivAccountResponse struct {
+	PrivAccount *account.PrivAccount
+}
+
+func GenPrivAccountHandler(w http.ResponseWriter, r *http.Request) {
+	privAccount := account.GenPrivAccount()
+
+	res := GenPrivAccountResponse{
+		PrivAccount: privAccount,
+	}
+	WriteAPIResponse(w, API_OK, res)
+}
+
+//-----------------------------------------------------------------------------
+
+type SignSendTxResponse struct {
+	SendTx *block.SendTx
+}
+
+func SignSendTxHandler(w http.ResponseWriter, r *http.Request) {
+	sendTxStr := GetParam(r, "sendTx")
+	privAccountsStr := GetParam(r, "privAccounts")
+
+	var err error
+	sendTx := binary.ReadJSON(&block.SendTx{}, []byte(sendTxStr), &err).(*block.SendTx)
+	if err != nil {
+		WriteAPIResponse(w, API_INVALID_PARAM, Fmt("Invalid sendTx: %v", err))
+		return
+	}
+	privAccounts := binary.ReadJSON([]*account.PrivAccount{}, []byte(privAccountsStr), &err).([]*account.PrivAccount)
+	if err != nil {
+		WriteAPIResponse(w, API_INVALID_PARAM, Fmt("Invalid privAccounts: %v", err))
+		return
+	}
+
+	for i, input := range sendTx.Inputs {
+		input.PubKey = privAccounts[i].PubKey
+		input.Signature = privAccounts[i].Sign(sendTx)
+	}
+
+	res := SignSendTxResponse{
+		SendTx: sendTx,
+	}
+	WriteAPIResponse(w, API_OK, res)
+}
diff --git a/rpc/blocks.go b/rpc/blocks.go
index c6d5e4c2..57be068e 100644
--- a/rpc/blocks.go
+++ b/rpc/blocks.go
@@ -21,11 +21,12 @@ func BlockchainInfoHandler(w http.ResponseWriter, r *http.Request) {
 		maxHeight = MinUint(blockStore.Height(), maxHeight)
 	}
 	if minHeight == 0 {
-		minHeight = MaxUint(1, MinUint(maxHeight-20, 1))
+		minHeight = uint(MaxInt(1, int(maxHeight)-20))
 	}
+	log.Debug("BlockchainInfoHandler", "maxHeight", maxHeight, "minHeight", minHeight)
 
 	blockMetas := []*BlockMeta{}
-	for height := minHeight; height <= maxHeight; height++ {
+	for height := maxHeight; height >= minHeight; height-- {
 		blockMeta := blockStore.LoadBlockMeta(height)
 		blockMetas = append(blockMetas, blockMeta)
 	}
@@ -41,6 +42,11 @@ func BlockchainInfoHandler(w http.ResponseWriter, r *http.Request) {
 
 //-----------------------------------------------------------------------------
 
+type BlockResponse struct {
+	BlockMeta *BlockMeta
+	Block     *Block
+}
+
 func BlockHandler(w http.ResponseWriter, r *http.Request) {
 	height, _ := GetParamUint(r, "height")
 	if height == 0 {
@@ -52,7 +58,12 @@ func BlockHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	blockMeta := blockStore.LoadBlockMeta(height)
 	block := blockStore.LoadBlock(height)
-	WriteAPIResponse(w, API_OK, block)
+	res := BlockResponse{
+		BlockMeta: blockMeta,
+		Block: block,
+	}
+	WriteAPIResponse(w, API_OK, res)
 	return
 }
diff --git a/rpc/http_handler.go b/rpc/http_handler.go
index 0f9ef39e..64529de9 100644
--- a/rpc/http_handler.go
+++ b/rpc/http_handler.go
@@ -43,6 +43,8 @@ func WriteAPIResponse(w http.ResponseWriter, status APIStatus, data interface{})
 	}
 
 	w.Header().Set("Content-Type", "application/json")
+	w.WriteHeader(200)
+	/* Bad idea: (e.g. hard to use with jQuery)
 	switch res.Status {
 	case API_OK:
 		w.WriteHeader(200)
@@ -56,7 +58,7 @@ func WriteAPIResponse(w http.ResponseWriter, status APIStatus, data interface{})
 		w.WriteHeader(430)
 	default:
 		w.WriteHeader(440)
-	}
+	}*/
 	w.Write(buf.Bytes())
 }
 
diff --git a/rpc/http_server.go b/rpc/http_server.go
index bd8d3b75..774f0c5e 100644
--- a/rpc/http_server.go
+++ b/rpc/http_server.go
@@ -12,6 +12,8 @@ func StartHTTPServer() {
 	http.HandleFunc("/blockchain", BlockchainInfoHandler)
 	http.HandleFunc("/block", BlockHandler)
 	http.HandleFunc("/broadcast_tx", BroadcastTxHandler)
+	http.HandleFunc("/gen_priv_account", GenPrivAccountHandler)
+	http.HandleFunc("/sign_send_tx", SignSendTxHandler)
 
 	log.Info(Fmt("Starting RPC HTTP server on %s", config.App.GetString("RPC.HTTP.ListenAddr")))
 
diff --git a/rpc/mempool.go b/rpc/mempool.go
index dafe7386..6bd795c3 100644
--- a/rpc/mempool.go
+++ b/rpc/mempool.go
@@ -11,7 +11,8 @@ import (
 func BroadcastTxHandler(w http.ResponseWriter, r *http.Request) {
 	txJSON := GetParam(r, "tx")
 	var err error
-	tx := ReadJSON(struct{ Tx }{}, []byte(txJSON), &err).(struct{ Tx }).Tx
+	var tx Tx
+	ReadJSON(&tx, []byte(txJSON), &err)
 	if err != nil {
 		WriteAPIResponse(w, API_INVALID_PARAM, Fmt("Invalid tx: %v", err))
 		return
diff --git a/state/state.go b/state/state.go
index 7541ef2c..e03bdcc6 100644
--- a/state/state.go
+++ b/state/state.go
@@ -110,7 +110,8 @@ func (s *State) Copy() *State {
 
 // The accounts from the TxInputs must either already have
 // account.PubKey.(type) != PubKeyNil, (it must be known),
-// or it must be specified in the TxInput.  But not both.
+// or it must be specified in the TxInput.  If redeclared,
+// the TxInput is modified and input.PubKey set to PubKeyNil.
 func (s *State) GetOrMakeAccounts(ins []*TxInput, outs []*TxOutput) (map[string]*Account, error) {
 	accounts := map[string]*Account{}
 	for _, in := range ins {
@@ -132,9 +133,7 @@ func (s *State) GetOrMakeAccounts(ins []*TxInput, outs []*TxOutput) (map[string]
 			}
 			account.PubKey = in.PubKey
 		} else {
-			if _, isNil := in.PubKey.(PubKeyNil); !isNil {
-				return nil, ErrTxRedeclaredPubKey
-			}
+			in.PubKey = PubKeyNil{}
 		}
 		accounts[string(in.Address)] = account
 	}
diff --git a/state/state_test.go b/state/state_test.go
index 5e13f82d..c2d81814 100644
--- a/state/state_test.go
+++ b/state/state_test.go
@@ -143,6 +143,75 @@ func TestGenesisSaveLoad(t *testing.T) {
 	}
 }
 
+/* TODO: Write better tests, and also refactor out common code
+func TestSendTxStateSave(t *testing.T) {
+
+	// Generate a state, save & load it.
+	s0, privAccounts, _ := RandGenesisState(10, true, 1000, 5, true, 1000)
+
+	sendTx := &SendTx{
+		Inputs: []*TxInput{
+			&TxInput{
+				Address:   privAccounts[0].PubKey.Address(),
+				Amount:    100,
+				Sequence:  1,
+				Signature: nil,
+				PubKey:    privAccounts[0].PubKey,
+			},
+		},
+		Outputs: []*TxOutput{
+			&TxOutput{
+				Address: []byte("01234567890123456789"),
+				Amount:  100,
+			},
+		},
+	}
+	sendTx.Inputs[0].Signature = privAccounts[0].Sign(sendTx)
+
+	// Mutate the state to append block with sendTx
+	block := &Block{
+		Header: &Header{
+			Network:        config.App.GetString("Network"),
+			Height:         1,
+			Time:           s0.LastBlockTime.Add(time.Minute),
+			Fees:           0,
+			NumTxs:         1,
+			LastBlockHash:  s0.LastBlockHash,
+			LastBlockParts: s0.LastBlockParts,
+			StateHash:      nil,
+		},
+		Validation: &Validation{},
+		Data: &Data{
+			Txs: []Tx{sendTx},
+		},
+	}
+	blockParts := NewPartSetFromData(BinaryBytes(block))
+
+	// The last argument to AppendBlock() is `false`,
+	// which sets Block.Header.StateHash.
+	err := s0.Copy().AppendBlock(block, blockParts.Header(), false)
+	if err != nil {
+		t.Error("Error appending initial block:", err)
+	}
+	if len(block.Header.StateHash) == 0 {
+		t.Error("Expected StateHash but got nothing.")
+	}
+
+	// Now append the block to s0.
+	// This time we also check the StateHash (as computed above).
+	err = s0.AppendBlock(block, blockParts.Header(), true)
+	if err != nil {
+		t.Error("Error appending initial block:", err)
+	}
+
+	// Save s0
+	s0.Save()
+	fmt.Printf("s0.accounts.Hash(): %X\n", s0.accounts.Hash())
+	s0.DB.Print()
+
+}
+*/
+
 func TestTxSequence(t *testing.T) {
 
 	state, privAccounts, _ := RandGenesisState(3, true, 1000, 1, true, 1000)