The race for presidential delegates has begun. Track them here.

The magic number to win the Democratic Party’s nomination for president is 1,991 delegates. It could take months to officially get there.

Presidential candidates are all competing for a majority of 3,979 pledged delegates. Separately, there are also 771 automatic delegates, otherwise known as “superdelegates.” But after a contentious 2016 primary, the Democratic National Committee changed its rules around superdelegates so they may now vote on the first ballot to select a nominee at the Democratic National Convention only if a campaign has secured a supermajority of pledged delegates. (Otherwise,...