Ed makes a very good point about turnout and its impact on the 2012 general election. Turnout depends on two main factors that are interrelated: 1) voter enthusiasm for the candidate and 2) the effectiveness of the operation that translates that enthusiasm into people actually showing up at the polls. The rule of thumb in campaigns is that the best turnout operations are worth two to three points, and as we’ve seen recently, that is often more than the margin of victory in many target states.

In 2004, the George W. Bush campaign believed that it had almost lost (or actually lost) the 2000 campaign because it lacked a strong get-out-the-vote effort. Karl Rove, Matthew Dowd and others built a turnout machine that ended up making the difference in what became a much closer election than some had believed.

One of the luxuries that President Obama has as an incumbent is the ability to use this entire primary season to refresh and extend his already impressive ground organization. If Ed is right, and the race comes down to turnout, I wouldn’t bet against the president.