diff --git a/cmd/mothd/httpd.go b/cmd/mothd/httpd.go
index 1963f63..541acb0 100644
--- a/cmd/mothd/httpd.go
+++ b/cmd/mothd/httpd.go
@@ -29,6 +29,7 @@ func NewHTTPServer(base string, server *MothServer) *HTTPServer {
 	h.HandleMothFunc("/", h.ThemeHandler)
 	h.HandleMothFunc("/state", h.StateHandler)
 	h.HandleMothFunc("/register", h.RegisterHandler)
+	h.HandleMothFunc("/assign", h.AssignParticipantHandler)
 	h.HandleMothFunc("/answer", h.AnswerHandler)
 	h.HandleMothFunc("/content/", h.ContentHandler)
 
@@ -132,7 +133,7 @@ func (h *HTTPServer) AssignParticipantHandler(mh MothRequestHandler, w http.Resp
 		return
 	}
 
-	if err := mh.AssignParticipant(); err != ErrAlreadyRegistered {
+	if err := mh.AssignParticipant(); err == ErrAlreadyRegistered {
 		jsend.Sendf(w, jsend.Success, "already assigned", "participant and team have already been associated")
 	} else if err != nil {
 		jsend.Sendf(w, jsend.Fail, "unable to associate participant and team", err.Error())
diff --git a/cmd/mothd/server.go b/cmd/mothd/server.go
index 900b6a9..87f4d73 100644
--- a/cmd/mothd/server.go
+++ b/cmd/mothd/server.go
@@ -139,6 +139,17 @@ func (mh *MothRequestHandler) PuzzlesOpen(cat string, points int, path string) (
 // CheckAnswer returns an error if answer is not a correct answer for puzzle points in category cat
 func (mh *MothRequestHandler) CheckAnswer(cat string, points int, answer string) error {
 	correct := false
+
+	teamID, err := mh.State.ParticipantTeam(mh.participantID)
+	
+	if err != nil {
+		return fmt.Errorf("invalid participant ID")
+	}
+
+	if _, err := mh.State.TeamName(teamID); err != nil {
+		return fmt.Errorf("invalid team ID")
+	}
+
 	for _, provider := range mh.PuzzleProviders {
 		if ok, err := provider.CheckAnswer(cat, points, answer); err != nil {
 			return err
@@ -146,20 +157,13 @@ func (mh *MothRequestHandler) CheckAnswer(cat string, points int, answer string)
 			correct = true
 		}
 	}
+
 	if !correct {
-		mh.State.LogEvent("wrong", mh.participantID, mh.teamID, cat, points)
+		mh.State.LogEvent("wrong", mh.participantID, teamID, cat, points)
 		return fmt.Errorf("incorrect answer")
 	}
 
-	mh.State.LogEvent("correct", mh.participantID, mh.teamID, cat, points)
-
-	if _, err := mh.State.TeamName(mh.teamID); err != nil {
-		return fmt.Errorf("invalid team ID")
-	}
-
-	if _, err := mh.State.ParticipantTeam(mh.participantID); err != nil {
-		return fmt.Errorf("invalid participant ID")
-	}
+	mh.State.LogEvent("correct", mh.participantID, teamID, cat, points)
 
 	if err := mh.State.AwardPoints(mh.participantID, cat, points); err != nil {
 		return fmt.Errorf("error awarding points: %s", err)
@@ -190,7 +194,7 @@ func (mh *MothRequestHandler) AssignParticipant() error {
 	}
 
 	if mh.teamID == "" {
-		return fmt.Errorf("empty participant ID")
+		return fmt.Errorf("empty team ID")
 	}
 
 	mh.State.LogEvent("assign", mh.participantID, mh.teamID, "", 0)
diff --git a/cmd/mothd/state.go b/cmd/mothd/state.go
index 40fa3f9..4183db5 100644
--- a/cmd/mothd/state.go
+++ b/cmd/mothd/state.go
@@ -183,6 +183,7 @@ func (s *State) ParticipantTeam(participantID string) (string, error) {
 	teamID, ok := s.participantTeams[participantID]
 	
 	if !ok {
+		fmt.Println("Could not find participant")
 		return "", fmt.Errorf("participant (%s) has not registered with a team", participantID)
 	}
 
diff --git a/theme/index.html b/theme/index.html
index f780301..c9d9ed0 100644
--- a/theme/index.html
+++ b/theme/index.html
@@ -16,11 +16,9 @@
       </div>
 
       <form id="login">
-        <!--
         <span id="pid">
-          Participant ID: <input name="pid"> (optional) <br>
+          Participant ID: <input name="pid"><br>
         </span>
-        -->
         Team ID: <input name="id"> <br>
         Team name: <input name="name"> <br>
         <input type="submit" value="Sign In">
diff --git a/theme/moth.js b/theme/moth.js
index eb1742c..6f32255 100644
--- a/theme/moth.js
+++ b/theme/moth.js
@@ -155,37 +155,74 @@ function login(e) {
   let pide = document.querySelector("[name=pid]")
   let participantId = pide?pide.value:Math.floor(Math.random() * Number.MAX_SAFE_INTEGER)
   
-  fetch("register", {
-    method: "POST",
-    body: new FormData(e.target),
-  })
-  .then(resp => {
-    if (resp.ok) {
-      resp.json()
-      .then(obj => {
-        if ((obj.status == "success") || (obj.data.short == "Already registered")) {
-          toast("Logged in")
-          sessionStorage.id = teamId
-          sessionStorage.pid = participantId
-          showPuzzles()
-          heartbeat()
-        } else {
-          toast(obj.data.description)
-        }
-      })
-      .catch(err => {
-        toast("Oops, the server has lost its mind. You probably need to tell someone so they can fix it.")
-        console.log(err, resp)
-      })
-    } else {
-      toast("Oops, something's wrong with the server. Try again in a few seconds.")
-      console.log(resp)
-    }
-  })
-  .catch(err => {
-    toast("Oops, something went wrong. Try again in a few seconds.")
-    console.log(err)
-  })
+  if (participantId != "") {
+    fetch("assign", {
+      method: "POST",
+      body: new FormData(e.target),
+    })
+    .then(resp => {
+      if (resp.ok) {
+        resp.json()
+        .then(obj => {
+          if ((obj.status == "success") || (obj.data.short == "already assigned")) {
+            toast("Logged in")
+            sessionStorage.id = teamId
+            sessionStorage.pid = participantId
+            showPuzzles()
+            heartbeat()
+          } else {
+            toast(obj.data.description)
+          }
+        })
+        .catch(err => {
+          toast("Oops, the server has lost its mind. You probably need to tell someone so they can fix it.")
+          console.log(err, resp)
+        })
+      } else {
+        toast("Oops, something's wrong with the server. Try again in a few seconds.")
+        console.log(resp)
+      }
+    })
+    .catch(err => {
+      toast("Oops, something went wrong. Try again in a few seconds.")
+      console.log(err)
+    })
+  } else {
+    toast("Participant ID may not be empty")
+  }
+
+  if (teamId != "") {
+    fetch("register", {
+      method: "POST",
+      body: new FormData(e.target),
+    })
+    .then(resp => {
+      if (resp.ok) {
+        resp.json()
+        .then(obj => {
+          if ((obj.status == "success") || (obj.data.short == "Already registered")) {
+            toast("Team registered")
+            
+          } else {
+            toast(obj.data.description)
+          }
+        })
+        .catch(err => {
+          toast("Oops, the server has lost its mind. You probably need to tell someone so they can fix it.")
+          console.log(err, resp)
+        })
+      } else {
+        toast("Oops, something's wrong with the server. Try again in a few seconds.")
+        console.log(resp)
+      }
+    })
+    .catch(err => {
+      toast("Oops, something went wrong. Try again in a few seconds.")
+      console.log(err)
+    })
+  } else {
+    toast("Team ID must be provided")
+  }
 }
 
 function init() {
diff --git a/theme/puzzle.html b/theme/puzzle.html
index 37206f6..f9d926b 100644
--- a/theme/puzzle.html
+++ b/theme/puzzle.html
@@ -22,7 +22,7 @@
       <input type="hidden" name="cat">
       <input type="hidden" name="points">
       <input type="hidden" name="xAnswer">
-      Team ID: <input type="text" name="id"> <br>
+      Participant ID: <input type="text" name="pid"> <br>
       Answer: <input type="text" name="answer" id="answer"> <span id="answer_ok"></span><br>
       <input type="submit" value="Submit">
     </form>
diff --git a/theme/puzzle.js b/theme/puzzle.js
index 9913878..cce7b6e 100644
--- a/theme/puzzle.js
+++ b/theme/puzzle.js
@@ -207,9 +207,14 @@ function init() {
     loadPuzzle(categoryName, points, puzzleId || points)
   }
 
-  let teamId = sessionStorage.getItem("id")
+  /*let teamId = sessionStorage.getItem("id")
   if (teamId) {
     document.querySelector("input[name=id]").value = teamId
+  }*/
+
+  let participantId = sessionStorage.getItem("pid")
+  if (participantId) {
+    document.querySelector("input[name=pid]").value = participantId
   }
   
   if (document.querySelector("#answer")) {