Evan Bayh shocked the political world today with his announcement that he will not seek reelection in 2010. Below is my post in response to the POLITICO Arena question on the topic. My former White House and Bush-Cheney ’04 colleague Rob Saliterman pointed out to me today the fate of a sitting President seems to be somewhat determined by whether or not they face a primary challenge when running for reelection. Rob noted: “no modern president who had a serious primary challenge has ever been reelected (LBJ, carter, 41) and no modern president who was unchallenged in the primary (eisenhower, nixon, clinton, 43) has ever lost reelection.” Wise point. Former Bush-Cheney 2000 and White House colleague Ken Lisaius suggested the primary challenge angle with Bayh. It could be him. It could be Dean. It could be someone else. If his approval numbers continue to slide, it can’t be ruled out as a possibility. Here’s my response from the POLITICO.

Democrat Sen. Evan Bayh won his last election by 24 percent. He won that race in 2004 at the same time President Bush won the state of Indiana by a 20 point margin. So, clearly Sen. Bayh has had the ability to attract crossover votes in his career. However, I would imagine he has seen an incredible erosion in his support since President Obama took office. For someone who has never lost election, Bayh must be looking to get out of the way of the GOP tidal wave that seems increasingly likely to sweep across the country in November. There’s also a chance that he’s looking to 2012. He may be trying to position himself as a moderate, somewhat non-partisan outsider who can run against a weakened, liberal President Obama. Engaging in a deeply partisan race for reelection this year against former Sen. Dan Coats wouldn’t serve that interest.