During the run-up to the primaries, Senator Obama did not appear in the Senate to vote on the Kyl-Lieberman Amendment calling on the government to designate the Iranian Revolutionary Guard Corps a terrorist entity and thus suffer the imposition of sanctions. On the day of the vote on the amendment, however, Obama issued a statement announcing that he would have voted against it. In the statement, the closest he came to addressing the merits of the amendment was his assertion that "he does not think that now is the time for saber-rattling towards Iran." The amendment passed the Senate 76-22 on September 26, 2007, with many Democrats including Hillary Clinton, Harry Reid, Richard Durbin, and Chuck Schumer voting in its favor.

Obama subsequently advanced three explanations for his opposition to the amendment. The McCain campaign usefully compiled them here. Obama mercilessly attacked Hillary Clinton for her vote in favor of the amendment...