Joe Biden’s withdrawal from the 2024 election has sent shockwaves through the political world—and while Biden has thrown his support behind Vice President Kamala Harris, that doesn’t mean her nomination as the party’s candidate is a lock.

With Biden out of the race, the delegates that were pledged to support him are free to vote for whomever they would like. They may, of course, be inclined to support Harris but are under no obligation to do so.

The endorsement of Harris should prevent a free-for-all at the convention, but other candidates could arise to challenge her, particularly given that Harris’ polling numbers have largely been parallel to Biden’s. (Harris’ 2020 presidential bid saw her peaking at just 15%, with the number falling to single digits before she dropped out.)

Expect party leaders to reach out to delegates with a message of unity. A fractured party will only give Trump and the Republicans another boost among voters.

Ohio’s outsize role

The Democrats had already planned a virtual vote, which officially locked in Biden as the nominee before the Democratic convention started on August 19. That was set up to ensure Biden was on the ballot in Ohio, which has an early-ballot deadline.

Legislators in Ohio resolved the potential problem of Biden not making the ballot in May, when Governor Mike DeWine called a special legislative session, where lawmakers passed a bill ensuring both candidates would be on the ballot. Democrats, however, could still hold the virtual vote, which would have the party begin its convention with a locked nominee and without the risk of it becoming a nationally televised three-ring circus.

If that virtual vote among delegates doesn’t happen, though, the 2024 Democratic Convention will be an open one, even if the party is fully behind Harris. That’s something that hasn’t happened since 1968 in Chicago, a Convention that was marred by a brutal police crackdown against protestors, most of whom were calling for the U.S. to withdraw from the Vietnam War.

What happens at an open convention 

Should the Democrats enter their Convention without the virtual vote, here’s how things will go:

Anyone can become a candidate for the Democratic nominee, as long as they gather the signatures of at least 300 delegates before or during the convention. (All totaled, there are 3,949 pledged delegates and 749 superdelegates who are able to vote.) On the first ballot, pledged delegates will vote for their candidate. If there’s a majority vote, that person becomes the nominee.

If not, there’s a second vote, which will include superdelegates, a group largely made up of the party’s leaders, including former presidents and vice presidents, members of Congress and party officials. (This would then be known as a “brokered” convention.) Superdelegates are not pledged to any particular candidate (and not a part of the first vote). The number of superdelegates varies by state, with California having the most (71). 

Again, if that second vote is necessary, when a candidate gets the majority of the votes, they’re chosen as the nominee. If not, voting will continue until one candidate comes out on top.

Multiple votes might make for more entertaining viewing for audiences, but discord at the Convention will likely not work out well for Democrats. The Republicans, in the meantime, will have weeks with a clearly chosen candidate able to demonstrate party unity and potentially win over voters.

Whoever becomes the Democratic nominee will have a lot of ground to catch up—and all of it mostly uncharted.