diff --git a/src/messages/MMonElection.h b/src/messages/MMonElection.h
index b589d9842f1..9771f6123d6 100644
--- a/src/messages/MMonElection.h
+++ b/src/messages/MMonElection.h
@@ -21,7 +21,7 @@
 
 class MMonElection : public Message {
 
-  static const int HEAD_VERSION = 3;
+  static const int HEAD_VERSION = 4;
   static const int COMPAT_VERSION = 2;
 
 public:
@@ -45,11 +45,20 @@ public:
   bufferlist monmap_bl;
   set<int> quorum;
   uint64_t quorum_features;
+  version_t paxos_first_version;
+  version_t paxos_last_version;
   
-  MMonElection() : Message(MSG_MON_ELECTION, HEAD_VERSION, COMPAT_VERSION) { }
-  MMonElection(int o, epoch_t e, MonMap *m)
+  MMonElection() : Message(MSG_MON_ELECTION, HEAD_VERSION, COMPAT_VERSION),
+    op(0), epoch(0), quorum_features(0), paxos_first_version(0),
+    paxos_last_version(0)
+  { }
+
+  MMonElection(int o, epoch_t e, MonMap *m,
+               version_t paxos_first, version_t paxos_last)
     : Message(MSG_MON_ELECTION, HEAD_VERSION, COMPAT_VERSION),
-      fsid(m->fsid), op(o), epoch(e), quorum_features(0) {
+      fsid(m->fsid), op(o), epoch(e), quorum_features(0),
+      paxos_first_version(paxos_first), paxos_last_version(paxos_last)
+  {
     // encode using full feature set; we will reencode for dest later,
     // if necessary
     m->encode(monmap_bl, CEPH_FEATURES_ALL);
@@ -78,6 +87,8 @@ public:
     ::encode(monmap_bl, payload);
     ::encode(quorum, payload);
     ::encode(quorum_features, payload);
+    ::encode(paxos_first_version, payload);
+    ::encode(paxos_last_version, payload);
   }
   void decode_payload() {
     bufferlist::iterator p = payload.begin();
@@ -93,6 +104,10 @@ public:
       ::decode(quorum_features, p);
     else
       quorum_features = 0;
+    if (header.version >= 4) {
+      ::decode(paxos_first_version, p);
+      ::decode(paxos_last_version, p);
+    }
   }
   
 };
diff --git a/src/mon/Elector.cc b/src/mon/Elector.cc
index 2b5bcc2ae88..122fe48846b 100644
--- a/src/mon/Elector.cc
+++ b/src/mon/Elector.cc
@@ -80,18 +80,21 @@ void Elector::start()
   electing_me = true;
   acked_me[mon->rank] = CEPH_FEATURES_ALL;
   leader_acked = -1;
+  acked_first_paxos_version = mon->paxos->get_first_committed();
 
   // bcast to everyone else
   for (unsigned i=0; i<mon->monmap->size(); ++i) {
     if ((int)i == mon->rank) continue;
-    Message *m = new MMonElection(MMonElection::OP_PROPOSE, epoch, mon->monmap);
+    Message *m = new MMonElection(MMonElection::OP_PROPOSE, epoch, mon->monmap,
+                                  mon->paxos->get_first_committed(),
+                                  mon->paxos->get_version());
     mon->messenger->send_message(m, mon->monmap->get_inst(i));
   }
   
   reset_timer();
 }
 
-void Elector::defer(int who)
+void Elector::defer(int who, version_t paxos_first)
 {
   dout(5) << "defer to " << who << dendl;
 
@@ -103,8 +106,11 @@ void Elector::defer(int who)
 
   // ack them
   leader_acked = who;
+  acked_first_paxos_version = paxos_first;
   ack_stamp = ceph_clock_now(g_ceph_context);
-  mon->messenger->send_message(new MMonElection(MMonElection::OP_ACK, epoch, mon->monmap),
+  mon->messenger->send_message(new MMonElection(MMonElection::OP_ACK, epoch, mon->monmap,
+                                                mon->paxos->get_first_committed(),
+                                                mon->paxos->get_version()),
 			       mon->monmap->get_inst(who));
   
   // set a timer
@@ -168,7 +174,10 @@ void Elector::victory()
        p != quorum.end();
        ++p) {
     if (*p == mon->rank) continue;
-    MMonElection *m = new MMonElection(MMonElection::OP_VICTORY, epoch, mon->monmap);
+    MMonElection *m = new MMonElection(MMonElection::OP_VICTORY, epoch,
+                                       mon->monmap,
+                                       mon->paxos->get_first_committed(),
+                                       mon->paxos->get_version());
     m->quorum = quorum;
     mon->messenger->send_message(m, mon->monmap->get_inst(*p));
   }
@@ -204,10 +213,13 @@ void Elector::handle_propose(MMonElection *m)
     }
   }
 
-  if (mon->rank < from) {
+  if ((mon->rank < from) &&
+      // be careful that we have new enough data to be leader!
+      (m->paxos_first_version <= mon->paxos->get_version())) {
     // i would win over them.
     if (leader_acked >= 0) {        // we already acked someone
-      assert(leader_acked < from);  // and they still win, of course
+      assert((leader_acked < from) || // and they still win, of course
+             (acked_first_paxos_version > mon->paxos->get_version()));
       dout(5) << "no, we already acked " << leader_acked << dendl;
     } else {
       // wait, i should win!
@@ -216,16 +228,20 @@ void Elector::handle_propose(MMonElection *m)
 	mon->start_election();
       }
     }
-  } else {
+  } else if (m->paxos_last_version >= mon->paxos->get_first_committed()) {
     // they would win over me
     if (leader_acked < 0 ||      // haven't acked anyone yet, or
 	leader_acked > from ||   // they would win over who you did ack, or
-	leader_acked == from) {  // this is the guy we're already deferring to
-      defer(from);
+	leader_acked == from) { // this is the guy we're already deferring to
+      defer(from, m->paxos_first_version);
     } else {
       // ignore them!
       dout(5) << "no, we already acked " << leader_acked << dendl;
     }
+  } else { // they are too out-of-date
+    dout(5) << "no, they are too far behind; paxos version: "
+	    << m->paxos_last_version << " versus my first "
+	    << mon->paxos->get_first_committed() << dendl;
   }
   
   m->put();
diff --git a/src/mon/Elector.h b/src/mon/Elector.h
index d81eb239763..9cce81e9f49 100644
--- a/src/mon/Elector.h
+++ b/src/mon/Elector.h
@@ -125,6 +125,10 @@ class Elector {
    * Indicates who we have acked
    */
   int	    leader_acked;
+  /**
+   * Indicates the first_paxos_commit on who we've acked
+   */
+  version_t acked_first_paxos_version;
   /**
    * Indicates when we have acked him
    */
@@ -197,16 +201,17 @@ class Elector {
    * to become the Leader. We will only defer an election if the monitor we
    * are deferring to outranks us.
    *
-   * @pre   @p who outranks us (i.e., who < our rank)
+   * @pre   @p who outranks us (who < our rank, or we're behind their store)
    * @pre   @p who outranks any other monitor we have deferred to in the past
    * @post  electing_me is false
    * @post  leader_acked equals @p who
    * @post  we sent an ack message to @p who
    * @post  we reset the expire_event timer
    *
-   * @param who Some other monitor's numeric identifier. 
+   * @param who Some other monitor's numeric identifier.
+   * @param paxos_first The other monitor's first committed paxos version
    */
-  void defer(int who);
+  void defer(int who, version_t paxos_first);
   /**
    * The election has taken too long and has expired.
    *
@@ -326,7 +331,8 @@ class Elector {
 			       epoch(0),
 			       participating(true),
 			       electing_me(false),
-			       leader_acked(-1) { }
+			       leader_acked(-1),
+			       acked_first_paxos_version(0) { }
 
   /**
    * Initiate the Elector class.
diff --git a/src/mon/Monitor.cc b/src/mon/Monitor.cc
index aabf5f1eb76..bd447a18701 100644
--- a/src/mon/Monitor.cc
+++ b/src/mon/Monitor.cc
@@ -1902,7 +1902,9 @@ void Monitor::handle_probe_reply(MMonProbe *m)
   if (m->quorum.size()) {
     dout(10) << " existing quorum " << m->quorum << dendl;
 
-    if (paxos->get_version() + g_conf->paxos_max_join_drift < m->paxos_last_version) {
+    if ((paxos->get_version() + g_conf->paxos_max_join_drift <
+	m->paxos_last_version) ||
+	(paxos->get_version() < m->paxos_first_version)){
       dout(10) << " peer paxos version " << m->paxos_last_version
 	       << " vs my version " << paxos->get_version()
 	       << " (too far ahead)"