Index: wp-includes/taxonomy.php
===================================================================
--- wp-includes/taxonomy.php	(revision 13330)
+++ wp-includes/taxonomy.php	(working copy)
@@ -1480,7 +1480,8 @@
 
 	if ( empty($slug) )
 		$slug = sanitize_title($name);
-	elseif ( is_term($slug) ) // Provided slug issue.
+	
+	if ( is_term($slug) ) // Provided slug issue.
 		return new WP_Error('term_slug_exists', __('A Term with the slug provided already exists.'));
 
 	$term_group = 0;