RUTHFULLY YOURS

The Senate class of 2012 incumbents running for re-election includes 21 Democrats, 2 independents who caucus with the Democrats (Joe Lieberman and Bernie Sanders), and 10 Republicans. Prior to the 2000 elections, this group of senators included 21 Republicans and 12 Democrats. Democrats picked up 5 seats in 2000, won another when Vermont Senator Jim Jeffords left the GOP, and won 6 more in 2006. The GOP won one seat back with Scott Brown’s victory in Massachusetts.

Many of the 21 Democrats know that there is a big target on their backs in 2012 from GOP challengers, serving as they do in states that went heavily for the GOP in the 2010 midterms and that elected Republicans as senators in 1994. Now there is a new problem: if these Democrats support the president’s tax compromise with the Republicans, a plan that is very unpopular with the left-wing base of the party, they could face primary challenges from the left.

At least ten of the Democratic incumbents already looked vulnerable at the start of the 2012 cycle: Sherrod Brown in Ohio, Herb Kohl in Wisconsin, Claire McCaskill in Missouri, Robert Menendez in New Jersey, Ben Nelson in Nebraska, Bill Nelson in Florida, Debbie Stabenow in Michigan, Jon Tester in Montana, Jim Webb in Virginia, and Kent Conrad in North Dakota. Some analysts might throw in Bob Casey in Pennsylvania. Joe Lieberman is a unique case. It is not clear on which ticket he will try to run in 2012. If he runs as a Democrat, he will surely face a left-wing challenger, and could lose the primary as he did in 2006.

Evidence of the threat ^[1] to these senators is the early activity on the Republican side in several of these races, with multiple candidates showing interest in a few of the states, and strong GOP challengers already emerging in Florida, Missouri, and Nebraska.

If the Democratic incumbents were assured they would be re-nominated, they could begin to position themselves early on for their re-election fight and move a bit towards the center to improve their chances with independents. Independent voters broke sharply for the Republicans in the 2010 midterms, with one of every three independents who voted with the Democrats in 2008 moving to the GOP in 2010. But there are now looming threats from the progressive wing of the party if some of these incumbents are seen as straying from the ideological path favored by the left on the tax bill.

Republicans look like they will hold at least 40 0f their 42 senators on the tax compromise. That means Democrats will need to supply 11 votes for a majority passage, or 20 votes to overcome a filibuster (the more likely scenario, with some hardcore senators such as Bernie Sanders pushing for this approach to block the bill). Minority Leader Mitch McConnell is optimistic that he will find the needed Democratic votes. But if he does, and some of them come from the class of 2012, who among them will serve their president now, only to face a primary challenger in two years?

The Blue Dog House members who voted for the cap and trade bill, voted for the health care reform bill, and then lost their seats in November 2010 might be able to offer some advice for their Senate colleagues about the upcoming vote. It is not at all certain, of course, that the votes are there in the House for passage, even though only a majority is needed in that body.

The House Democrats are a more ideologically driven group than the Senate Democrats, and class warfare on the tax issue is a first principle. That is why the president and Harry Reid have elected to make the Senate vote first on the tax bill. If the bill passes the Senate, that would put more pressure on wavering Democratic holdouts in the House, particularly some of the Blue Dogs, who did the bidding of the left once or twice and paid the price in their re-election bids. Some of these House Democrats may want another shot at their seat in 2012. Helping to kill the bill and allowing tax rates to go up for most Americans hardly seems lik  a recipe to win the next time around.

Serious primary challenges inevitably weaken an incumbent, even if he or she survives. Arkansas Senator Blanche Lincoln angered the big unions with some of her votes and was challenged from the left in 2010. She had an expensive, hard-fought primary race that included a runoff  that she won narrowly. But Lincoln was bruised and underfunded heading into the general election, which she lost decisively to Congressman John Boozman.

In 2010, the Republican Party establishment felt the wrath of the Tea Party, as incumbents were taken down in primaries or state conventions in Alaska and Utah, and the establishment candidates in several open-seat races were defeated by Tea Party challengers in Kentucky, Colorado, Nevada, Delaware, and Florida. Some of the Tea Party-backed candidates proved to be strong general election candidates, such as Marco Rubio in Florida, and Rand Paul improved as a candidate after a shaky start. Others were weaker (Ken Buck, Sharron Angle, Joe Miller) or had no chance (Christine O’Donnell), and Republicans lost several seats that were very winnable in a strong GOP wave in 2010.

If left-wing activists go after Senate Democrats running in 2012 who vote for the tax compromise, it will weaken these incumbents if they hold on to win the primary and make a GOP pickup of some of these targeted seats  more likely. If left-wing challengers win some primaries, it is not clear that they could win general election fights  in some of the states that moved right in 2010.

This is not to say that Tea Party challengers to GOP Senate incumbents are now over and done with. Richard Lugar of Indiana and Olympia Snowe of Maine are both very popular in their states and would likely be easy winners if nominated for re-election, but they may face challengers from the right. In Indiana, it might not matter who the GOP nominee is — he or she would be favored to win. That is not the case in Maine.

In the new age of demands for greater ideological purity in both parties, the chances for substantive compromises diminish.  So the GOP will continue to push taxes lower. And the Democrats will continue to spend. And the deficit will continue to grow. The deficit commission laid out some of what I think could be called substantive compromises on spending and taxes. But senators facing potential challenges from the left or right may be very wary of these kind of compromises, which anger their base.