Obama web ad: 'Blank Check' (video 01:17))
The ad replays Obama's 2002 anti-war speech, and casts him as a lone voice against the war. Also, an oblique contrast with Hillary's vote on Kyl-Lieberman's anti-Iran resolution:
"He's fighting to end it now, and to prevent history from repeating itself."
Relatedly, don't miss Obama's Union Leader op-ed, in which he goes far more directly at Hillary for supporting a "reckless" resolution that, he argues, links Iraq and Iran. (This was, for most, a secondary objection; but Obama has said he agrees with the best-known part of the resolution, which labeled the Revolutionary Guard a terror group.)