diff --git a/django/db/models/base.py b/django/db/models/base.py
index f2dd924381..bffd504f53 100644
--- a/django/db/models/base.py
+++ b/django/db/models/base.py
@@ -190,11 +190,16 @@ class Model(object):
     save.alters_data = True
 
     def __collect_sub_objects(self, seen_objs):
+        """
+        Recursively populates seen_objs with all objects related to this object.
+        When done, seen_objs will be in the format:
+            {model_class: {pk_val: obj, pk_val: obj, ...},
+             model_class: {pk_val: obj, pk_val: obj, ...}, ...}
+        """
         pk_val = self._get_pk_val()
-
         if pk_val in seen_objs.setdefault(self.__class__, {}):
             return
-        seen_objs.setdefault(self.__class__, {})[pk_val] = (self, True)
+        seen_objs.setdefault(self.__class__, {})[pk_val] = self
 
         for related in self._meta.get_all_related_objects():
             rel_opts_name = related.get_method_name_part()
@@ -209,63 +214,48 @@ class Model(object):
                 for sub_obj in getattr(self, 'get_%s_list' % rel_opts_name)():
                     sub_obj.__collect_sub_objects(seen_objs)
 
-    def delete(self, ignore_objects=None):
-        assert self._get_pk_val() is not None, "%r can't be deleted because it doesn't have an ID."
-        seen_objs = {}
-        if ignore_objects:
-            for obj in ignore_objects:
-                ignore_objs.setdefault(self.__class__,{})[obj._get_pk_val()] = (obj, False)
-
+    def delete(self):
+        assert self._get_pk_val() is not None, "%s object can't be deleted because its %s attribute is set to None." % (self._meta.object_name, self._meta.pk.attname)
         seen_objs = {}
         self.__collect_sub_objects(seen_objs)
 
-        #TODO: create a total class ordering rather than this sorting, which is
-        # only a partial ordering, and also is done each delete..
-        seen_cls = set(seen_objs.keys())
-        cls_order = list(seen_cls)
-        cls_order.sort(cmp_cls)
+        seen_classes = set(seen_objs.keys())
+        ordered_classes = list(seen_classes)
+        ordered_classes.sort(cmp_cls)
 
         cursor = connection.cursor()
 
-        for cls in cls_order:
+        for cls in ordered_classes:
             seen_objs[cls] = seen_objs[cls].items()
             seen_objs[cls].sort()
-            for pk_val, (instance, do_delete) in seen_objs[cls]:
+            for pk_val, instance in seen_objs[cls]:
+                dispatcher.send(signal=signals.pre_delete, sender=cls, instance=instance)
 
-                # Run any pre-delete hooks.
-                if do_delete:
-                    dispatcher.send(signal=signals.pre_delete, sender=cls, instance=instance)
-
-                    for related in cls._meta.get_all_related_many_to_many_objects():
-                        cursor.execute("DELETE FROM %s WHERE %s=%%s" % \
-                            (backend.quote_name(related.field.get_m2m_db_table(related.opts)),
-                            backend.quote_name(cls._meta.object_name.lower() + '_id')),
-                            [pk_val])
-                    for f in cls._meta.many_to_many:
-                        cursor.execute("DELETE FROM %s WHERE %s=%%s" % \
-                            (backend.quote_name(f.get_m2m_db_table(cls._meta)),
-                            backend.quote_name(cls._meta.object_name.lower() + '_id')),
-                            [pk_val])
-
-                    for field in cls._meta.fields:
-                        if field.rel and field.null and field.rel.to in seen_cls:
-                            cursor.execute("UPDATE %s SET %s = NULL WHERE %s=%%s" % \
-                                (backend.quote_name(cls._meta.db_table), backend.quote_name(field.column),
-                                backend.quote_name(cls._meta.pk.column)), [pk_val])
-                            setattr(instance, field.attname, None)
-
-        for cls in cls_order:
-            seen_objs[cls].reverse()
-
-            for pk_val, (instance, do_delete) in seen_objs[cls]:
-                if do_delete:
+                for related in cls._meta.get_all_related_many_to_many_objects():
                     cursor.execute("DELETE FROM %s WHERE %s=%%s" % \
-                        (backend.quote_name(cls._meta.db_table), backend.quote_name(cls._meta.pk.column)),
+                        (backend.quote_name(related.field.get_m2m_db_table(related.opts)),
+                        backend.quote_name(cls._meta.object_name.lower() + '_id')),
                         [pk_val])
+                for f in cls._meta.many_to_many:
+                    cursor.execute("DELETE FROM %s WHERE %s=%%s" % \
+                        (backend.quote_name(f.get_m2m_db_table(cls._meta)),
+                        backend.quote_name(cls._meta.object_name.lower() + '_id')),
+                        [pk_val])
+                for field in cls._meta.fields:
+                    if field.rel and field.null and field.rel.to in seen_classes:
+                        cursor.execute("UPDATE %s SET %s=NULL WHERE %s=%%s" % \
+                            (backend.quote_name(cls._meta.db_table), backend.quote_name(field.column),
+                            backend.quote_name(cls._meta.pk.column)), [pk_val])
+                        setattr(instance, field.attname, None)
 
-                    setattr(instance, cls._meta.pk.attname, None)
-
-                    dispatcher.send(signal=signals.post_delete, sender=cls, instance=instance)
+        for cls in ordered_classes:
+            seen_objs[cls].reverse()
+            for pk_val, instance in seen_objs[cls]:
+                cursor.execute("DELETE FROM %s WHERE %s=%%s" % \
+                    (backend.quote_name(cls._meta.db_table), backend.quote_name(cls._meta.pk.column)),
+                    [pk_val])
+                setattr(instance, cls._meta.pk.attname, None)
+                dispatcher.send(signal=signals.post_delete, sender=cls, instance=instance)
 
         connection.commit()