The GOP Senate victories of 2010 have made Republicans hungry for additional gains. On paper, they enjoy a big advantage in 2012, because only ten of their seats are up for election, compared with 23 seats of senators who caucus with the Democrats. The GOP is especially eager to seize pickup opportunities in right-leaning states such as Montana, Nebraska, and North Dakota.
Before any red-state Republican can go on the attack, however, a few may find themselves playing defense. If 2010 holds any lesson for incumbents, it’s that conservative voters are willing to mutiny against moderates. Two Republican senators, Robert Bennett of Utah and Lisa Murkowski of Alaska, fell to primary challengers. A third, Arlen Specter of Pennsylvania, chose to switch parties rather than face GOP voters. All were victims of rivals who harnessed the energies of the Tea Party movement, whose influence is more likely to grow than shrink over the next two years.