Index: wp-includes/nav-menu.php
===================================================================
--- wp-includes/nav-menu.php	(revision 18317)
+++ wp-includes/nav-menu.php	(working copy)
@@ -22,17 +22,17 @@
 	if ( ! $menu )
 		return false;
 
-	$menu_obj = get_term( $menu, 'nav_menu' );
+	$menu_obj = false;
 
+	if ( is_numeric( $menu ) )
+		$menu_obj = get_term( intval( $menu ), 'nav_menu' );
+
 	if ( ! $menu_obj )
 		$menu_obj = get_term_by( 'slug', $menu, 'nav_menu' );
 
 	if ( ! $menu_obj )
 		$menu_obj = get_term_by( 'name', $menu, 'nav_menu' );
 
-	if ( ! $menu_obj )
-		$menu_obj = false;
-
 	return $menu_obj;
 }