Keller @ Large: Carson's Memory Lapse

BOSTON (CBS) - When you take the lead in a presidential race you can expect to have everything you've ever said or written scrutinized and double-checked, and when discrepancies emerge, you'd better be ready to deal with it.

Just ask Ben Carson and his newly-ascendant Republican presidential campaign.

Friday's Politico report in which the Carson campaign concedes his past claims of acceptance at the US Military Academy at West Point were false comes on the heels of questions about his stories of violent encounters growing up in Detroit. The latter haven't been proven false, but put it all together in one news cycle and you have the prospect of doubts being raised about Carson's credibility just as many voters are giving him a good look for the first time.

In politics, timing is everything, and this is bad timing for Carson. His campaign is pushing back hard against the media on this, and that might help, especially among his core supporters and others who just can't stand the way the press goes after candidates.

But here are the keys for Carson -- is there more to come, and how quickly can he move past all this? The next GOP debate is Tuesday night. (Tune in Tuesday at 11pm for highlights and analysis on WBZ News.) Will he spend his time on defense, or find a way to change the subject?