diff --git a/archivebox/core/admin.py b/archivebox/core/admin.py
index 517ec79b..91feb07b 100644
--- a/archivebox/core/admin.py
+++ b/archivebox/core/admin.py
@@ -213,10 +213,9 @@ class SnapshotAdmin(SearchResultsAdminMixin, admin.ModelAdmin):
     delete_snapshots.short_description = "Delete"
 
     def add_tag(self, request, queryset):
-        if tag and tag.id:
-            tag = request.POST['tag']
-            for obj in queryset:
-                obj.tags.add(tag)
+        tag = request.POST['tag']
+        for obj in queryset:
+            obj.tags.add(tag)
 
     add_tag.short_description = "Add tag"