Last night, on the eve of the most momentous protest rally this side of the Persian Gulf, David Letterman took a few minutes out of his show to fully explain last week’s widely denounced Palin joke, and to sincerely apologize to all who were offended. He reiterated, again, that he never meant to target 14-year-old Willow Palin and had no idea she was at the Yankee game where A-Rod hypothetically knocked her up. All he was trying to do was mock the sluttiness of the other Palin daughter, as every other late-night comedian has done ad nauseam. John McCain, already tired of Palin even before this all started, tweeted his satisfaction this morning: “Letterman apologizes and did the right thing — time to move on.” Indeed it is. Oh, except that rally planned for this afternoon outside of Letterman’s studios is reportedly still going ahead as planned, for some reason.