What Super Tuesday Means for Democratic Delegate Math

The unsettled nature of the Democratic presidential race means it could be competitive right until, and perhaps through, the party’s convention in July. That could test the party’s rules and traditions in choosing a nominee, potentially unleashing the first contested convention of either major U.S. political party in almost 70 years.

State by state, candidates accumulate so-called pledged delegates who will support them on the first ballot at the convention, being held in Milwaukee the week of July 13. Delegates used to be picked by party bosses, but since 1972 they’re increasingly apportioned through primaries and (less so) caucuses, being held this year from Feb. 3 to June 6. To win, a candidate needs to have a majority, 1,991, of the 3,979 pledged delegates on the first ballot. (Unpledged “superdelegates” enter the picture if nobody wins on the first ballot. More on them later.)