Biden AdministrationUkraine InvasionInflationEnergyCybersecurity

How a contested Democratic convention would work

February 27, 2020, 4:00 PM UTC

With a big field of candidates and no clear front-runner, the Democratic presidential race 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.

1. What does it take to win the Democratic nomination?

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.)

2. Which primaries award the most delegates?

The 14 states holding Democratic primaries on March 3, this year’s so-called Super Tuesday, will award a total of 1,357 pledged delegates, 34% of the total. States in play that day include the nation’s two most populous, California and Texas, plus Alabama, Arkansas, Colorado, Maine, Massachusetts, Minnesota, North Carolina, Oklahoma, Tennessee, Utah, Vermont and Virginia. Other major days on the primary calendar are March 17, when Florida is among four states voting, and April 28, when New York’s primary is one of six.

3. How are delegates awarded?

Unlike the Republican Party, which allows “winner-take-all” primaries, Democrats award delegates proportionally, so multiple candidates can share in a state’s bounty of pledged delegates. Only about 25% of delegates go to the statewide winner, with the rest dependent on results in specific congressional or legislative districts. Any candidate who wins at least 15% of votes cast statewide or in a district gets at least some delegates.

4. Will this process produce a presumptive nominee before the convention?

Recent history says yes: The last multiple-ballot “contested” conventions were in 1952 for both Democrats and Republicans. But this year might be unusual. Five candidates won at least some delegates in the first two contests, in Iowa and New Hampshire, and two others — billionaires Michael Bloomberg and Tom Steyer — are spending personal fortunes in hopes of winning delegates on Super Tuesday. (Bloomberg is the founder and majority owner of Bloomberg LP, the parent company of Bloomberg News.) Both parties managed to avert contested conventions in recent decades because runners-up were willing to drop out or release their pledged delegates to support the eventual nominee. But with this year’s race looking like a battle for the party’s soul, normal rules may not apply. If three (or more) candidates endure deep into primary season, with enough strength to get a share of each state’s pot, a contested convention may become unavoidable. As of Feb. 21, the political website fivethirtyeight.com assigned a 42% chance to no Democrat winning a majority of pledged delegates before the convention.

5. What would a contested convention look like?

If no candidate receives 1,991 votes during the first roll call of states, pledged delegates are released from their obligations and can switch their support as they see fit, and the unpledged superdelegates can weigh in on the second (and any further) ballot. Voting continues until someone wins a majority — 2,376 — of this enlarged pool of 4,750 delegates. The realigning and deal-making that would follow an indecisive first ballot could in theory lead to a dark horse becoming the nominee, perhaps even someone who didn’t campaign in the primaries. Contested conventions used to be known as “brokered” because party bosses selected the nominee through back-room deals. The primary system has reduced the influence of those bosses, so a more accurate term these days might be “open” convention.

6. Who gets to be a superdelegate?

Members of Congress, governors, Democratic National Committee members and other “distinguished party leaders.” Though these automatic delegates (as the party prefers to call them) can vote for any candidate, they often reflect the wishes of voters in their states. There are 771 of these delegates, about 17% of the total. Once seen as an emergency brake on a populist wave that could nominate an unacceptable candidate, superdelegates were made less powerful — unable to vote on a first ballot unless its outcome is not in doubt — after the 2016 Democratic nominating contest, when superdelegates came out early and in large numbers for Hillary Clinton, angering supporters of that year’s runner-up, Bernie Sanders.

More must-read stories from Fortune:

—Are we undergoing an industrial revolution or a phase change?
—Understanding the 2020 election as brand marketing
Investors shouldn’t underestimate election volatility, warns UBS
—Angela Merkel is on her way out. Meet her potential replacements
How the 2020 election could influence your personal finances

Get up to speed on your morning commute with Fortune’s CEO Daily newsletter.