1. Sen. Jon Kyl (R-AZ): The Senate's second highest ranking Republican made a name for himself by nuking the comprehensive test ban treaty back in the late 90s. He tried to undertake a similar effort during the lame duck with the New START. Frankly, he got rolled, and he took his leader, Sen. Mitch McConnell (R-KY), with him. After he got rolled, his allies in the GOP whined about how it was disrespectful of the Senate not to let him kill the treaty. That didn't help his cause.
2. Sen. John McCain (R-AZ): Mr. Congeniality lost (at least for now) his toady friends in the mainstream media by completely losing his composure over DADT. "There'll be high fives all over the liberal bastions of America...most of them have never served in the military, or maybe even not even known someone in the military," he claimed. He also pointed out, ruefully, that there are marines at Walter Reed Army Medical Center without any limbs... as if the bombs exploded because they knew DADT might be repealed.
3. Sen. Joe Manchin (D-WV): After voting against a defense bill that contained a DADT repeal provision -- the only Democrat to do so -- Manchin caught a lot of flack from liberals. So when repeal came up again as a stand-alone measure, paired with a vote on the DREAM Act he skipped town to reportedly attend a holiday party instead of voting. That didn't improve the situation for him.
4. Immigrants: Democrats didn't pass every item on their agenda during the lame duck. The DREAM act, which would have given children of illegal immigrants a path to citizenship if they received a college education and/or enlisted in the military, was the big one that got away. It remains a top Democratic priority, though -- and a good campaign issue for some Democrats going into 2012.
5. House Democratic Leadership: Once the White House got involved, House liberals basically lost their chance to enact a truly progressive tax plan. But they did have a couple opportunities to force a showdown with President Obama and the GOP by withholding their support for the negotiated compromise that ultimately passed. Instead, they: passed a separate plan -- to let tax cuts for the wealthy expire -- that would clearly fail in the Senate; and agreed to a non-binding resolution of disapproval with the President's bill; and pitched a symbolic fit on the day of the final vote before giving Obama enough support to hand him a victory.