Index: wp-includes/comment-template.php
===================================================================
--- wp-includes/comment-template.php	(revision 21298)
+++ wp-includes/comment-template.php	(working copy)
@@ -907,7 +907,7 @@
 		$overridden_cpage = true;
 	}
 
-	if ( !defined('COMMENTS_TEMPLATE') || !COMMENTS_TEMPLATE)
+	if ( !defined('COMMENTS_TEMPLATE') )
 		define('COMMENTS_TEMPLATE', true);
 
 	$include = apply_filters('comments_template', STYLESHEETPATH . $file );