No, not Chris Matthews to Keith Olbermann.  That media odd couple have already begun to kiss and make up. Instead, it was Joe Scarborough who authored the line this morning, directing it at Obama spokesman Mark Bubriski.  The cause of Joe's ire was this email statement Bubriski released to the Miami Herald [emphasis added]:

Palin was a supporter of Pat Buchanan, a right-winger or as many Jews call him: a Nazi sympathizer.

The Morning Joe crew was unanimous in roundly condemning the Obama campaign tactic, rallying around Buchanan, one of its own, who was present on the set.  Bubriski was riffing off a similar allegation made by Bob Wexler, a south Florida Dem congressman.  

View video here.  It's perhaps the longest video clip I've posted, but hope you'll agree the content justifies the length. Joe unleashes on Bubriski [calling him a "jackass" for good measure] three minutes in.