diff --git a/openslides/assignment/models.py b/openslides/assignment/models.py
index bf288cd8e..accfc2105 100644
--- a/openslides/assignment/models.py
+++ b/openslides/assignment/models.py
@@ -33,6 +33,7 @@ class AssignmentCandidate(models.Model):
     assignment = models.ForeignKey("Assignment")
     person = PersonField(db_index=True)
     elected = models.BooleanField(default=False)
+    blocked = models.BooleanField(default=False)
 
     def __unicode__(self):
         return unicode(self.person)
@@ -72,6 +73,8 @@ class Assignment(models.Model, SlideMixin):
     def run(self, candidate, person=None):
         """
         run for a vote
+        candidate: The user who will be a candidate
+        person: The user who chooses the candidate
         """
         # TODO: don't make any permission checks here.
         #       Use other Exceptions
@@ -79,23 +82,39 @@ class Assignment(models.Model, SlideMixin):
             raise NameError(_('<b>%s</b> is already a candidate.') % candidate)
         if not person.has_perm("assignment.can_manage_assignment") and self.status != 'sea':
             raise NameError(_('The candidate list is already closed.'))
-        AssignmentCandidate(assignment=self, person=candidate, elected=False).save()
+        candidation = self.assignment_candidats.filter(person=candidate)
+        if candidation and candidate != person:
+            # if the candidation is blocked and anotherone tries to run the
+            # candidate
+            raise NameError(
+                _('The %s does not want to be a candidate.') % candidate)
+        elif candidation and candidate == person:
+            candidation[0].blocked = False
+            candidation[0].save()
+        else:
+            AssignmentCandidate(assignment=self, person=candidate).save()
 
-    def delrun(self, candidate):
+    def delrun(self, candidate, blocked=True):
         """
         stop running for a vote
         """
         if self.is_candidate(candidate):
-            self.assignment_candidats.get(person=candidate).delete()
+            candidation = self.assignment_candidats.get(person=candidate)
+            if blocked:
+                candidation.blocked = True
+                candidation.save()
+            else:
+                candidation.delete()
         else:
             # TODO: Use an OpenSlides Error
             raise Exception(_('%s is no candidate') % candidate)
 
     def is_candidate(self, person):
-        if self.assignment_candidats.filter(person=person).exists():
-            return True
-        else:
-            return False
+        """
+        return True, if person is a candidate.
+        """
+        return self.assignment_candidats.filter(person=person) \
+                   .exclude(blocked=True).exists()
 
     @property
     def assignment_candidats(self):
@@ -110,7 +129,7 @@ class Assignment(models.Model, SlideMixin):
         return self.get_participants(only_elected=True)
 
     def get_participants(self, only_elected=False, only_candidate=False):
-        candidates = self.assignment_candidats
+        candidates = self.assignment_candidats.exclude(blocked=True)
 
         if only_elected and only_candidate:
             # TODO: Use right Exception
diff --git a/openslides/assignment/views.py b/openslides/assignment/views.py
index 1e76e0999..83b5e04c5 100644
--- a/openslides/assignment/views.py
+++ b/openslides/assignment/views.py
@@ -81,9 +81,12 @@ def view(request, assignment_id=None):
                 user = form.cleaned_data['candidate']
                 try:
                     assignment.run(user, request.user)
-                    messages.success(request, _("Candidate <b>%s</b> was nominated successfully.") % (user))
                 except NameError, e:
                     messages.error(request, e)
+                else:
+                    messages.success(request, _(
+                        "Candidate <b>%s</b> was nominated successfully.")
+                        % user)
     else:
         if request.user.has_perm('assignment.can_nominate_other'):
             form = AssignmentRunForm()
@@ -184,7 +187,7 @@ def delrun(request, assignment_id):
     assignment = Assignment.objects.get(pk=assignment_id)
     try:
         if assignment.status == 'sea' or user.has_perm("assignment.can_manage_assignment"):
-            assignment.delrun(request.user)
+            assignment.delrun(request.user, blocked=True)
         else:
             messages.error(request, _('The candidate list is already closed.'))
     except Exception, e:
@@ -201,7 +204,7 @@ def delother(request, assignment_id, user_id):
 
     if request.method == 'POST':
         try:
-            assignment.delrun(person)
+            assignment.delrun(person, blocked=False)
         except Exception, e:
             messages.error(request, e)
         else: