Mark,
My prediction about the 2012 election going Republican if Republicans should regain control of Congress this fall is based on the near-total domination that the huge multinational corporations and the well-funded right-wing think tanks and sting-pullers already have on our voting systems and the media and the courts.    There is some hope of some push-back against that if the Dems retain power and if -- and this is a huge "if" -- they finally show both some wisdom and some backbone in standing up to those forces.
But if the speculation is correct that the moneyed corporations are holding back on letting their cash "trickle down" either until the Republicans regain power or until the recession/depression has run its course, and if the economy bounces back only after the Democrats have been defeated, I don't think it matters who the Dems run in 2012. They will lose.
Way too many voters are stupid and gullible and the media exacerbate that by their sloppy and/or biased reporting and commentary.