May 20

May 20 -- that's the date when the campaign unofficially expects to "clinch" the nomination -- when they'll officially have a majority of pledged delegates, which triggers, in their view, the standard for superdelegate decision-making set by party leaders like Nancy Pelosi. As of tonight, Obama will be between 35 and 43 pledged delegates votes away from achieving that majority.

This article available online at:

http://www.theatlantic.com/politics/archive/2008/05/may-20/52997/