General David Petraeus put his superstar, celebrity-like reputation on the line when he made the media rounds last week touting the message that the US is making significant progress in Afghanistan.

The communications challenges of selling what has become a drawn-out and increasingly unpopular war are formidable. American troop casualties reached a record high in July, pushing the total number of deaths well beyond the 1,000 mark. The House recently approved $37 billion in new spending for the campaign ...