By John Dickerson|Posted Thursday, Feb. 23, 2012, at 1:17 AM ET

Justin Sullivan

The 20th and perhaps final Republican presidential debate wheezed across the finish line and collapsed. At times it felt like the candidates had already talked themselves out on the big themes and could only bicker over table scraps. There was a long symposium on how earmarks and the congressional appropriating process work. Then, there was a confusing discussion of Arlen Specter, his re-election, and the judiciary committee. 

Who won? Ask the undecided Republicans in Michigan. They count the most tonight. Though the debate was held in Arizona, and there were some sturdy local panders to the state's immigration law, the most important audience was in a state 50...