Conservatives endorsing Obama, also known as the "flight to quality"*
http://blogs.tnr.com/tnr/blogs/the_plank/archive/2008/10/24/reagan-appointee-and-recent-mccain-adviser-charles-fried-supports-obama.aspx
I've been seeing lots of these kind of endorsements lately. Pretty much all of them mention the Palin choice as VP as the deal breaker.
*term coined by Josh Marshall over at Talking Points Memo-
http://www.talkingpointsmemo.com/archives/239669.php