Clive Crook writes that should the Democrats in Congress get beaten badly in November, Obama "would have to be a centrist president or an outright failure." Brendan Nyhan counters:

Bill Clinton's much-vaunted move to the center may have helped boost his margin in 1996, but improvements in the state of the economy surely played a more important role in the outcome. The "best hope for the Obama presidency" isn't a "drubbing for Democrats in November"; it's a period of sustained economic growth that will boost Obama's approval numbers and increase the likelihood that he'll be re-elected in 2012.