Why We Have a Long Democratic Primary Season Ahead of Us

It looks like the split of votes (and delegates) on Feb. 5 is likely to give no more than 60% of the delegates cast that day to one candidate or the other. That means both Obama and Clinton will be a long way from reaching the 50% majority of TOTAL delegates they need to claim the nomination. Below I've graphed the cumulative number of delegates committed by date. The percentages are based only on pledged delegates (the ones selected by voting) but are calculated as a percentage of the overall total (pledged + unpledged).

A candidate needs 50% of the total to get the nomination. Fifty percent of the total votes won't even be cast until Feb. 9, and it's not until April 22 that the 70% line is crossed. There's a long lag between the March 11 primary in Mississippi--after which 66% of the delegates will be committed--and the April 22 contest in Pennsylvania. My guess is the race won't be decided until that April 22 contest at the earliest, and it could well go all the way to the convention in August, when the superdelegates (who make up the remaining 20%) make their choice.
UPDATE: Paul Krugman seems surprised by this conclusion, which makes me wonder what he's been thinking. At least since South Carolina it's been clear that this thing's going to go a while.