In 2012, just 10 Republicans in the U.S. Senate will likely be running for re-election, compared to 23 Democrats and allied independents. Suppose that the Senate winds up being unable to extend the Bush tax cuts, which expire Dec. 31, because Democrats stick to their position that the richest Americans shouldn't get this tax break and Republicans refuse a compromise that would limit cuts to those earning $250,000 and under. Who would face the greater political risk when middle-class, independent voters - the swing voters - head to the polls in 2012 to take vengeance for their higher taxes? The 10 incumbent Senate Republicans or the 23 Democrats and President Obama?Given the march of independents to the Republican column in the 2010 election, there is every reason to believe that the greater risk falls on Democrats, and especially on Obama, who, yes, did pledge time and again not to extend tax cuts to the rich but also promised to negotiate with the Republicans.MoveOn.org, busily raising donations by highlighting the tax cuts dispute, has begun a "We Want Our Obama Back" advertising campaign on this subject. Along with Paul Krugman, MoveOn is willing to further dampen liberal enthusiasm for Obama even if it means ceding the 2012 election to the Republicans. And yet Obama has little choice politically but to reach a compromise on the tax rate.