Shortly after Biden announced he was dropping out of the race, he issued a second statement endorsing Harris for the presidential nomination. Harris has since received a number of additional key endorsements, including from Bill and Hillary Clinton, influential congressman Rep. Jim Clyburn and Sen. Elizabeth Warren. Potential rivals such as California Gov. Gavin Newsom and Secretary of Transportation Pete Buttigieg have also endorsed Harris; both gentleman are potential running mates should Harris get the nomination. Additionally, Harris has received support from leaders or representatives of the Congressional Black Caucus, the Congressional Hispanic Caucus and the Congressional Progressive Caucus.

Despite the support for Harris coming from Biden and others and her position as Biden’s vice president and running mate, she does not automatically receive the nomination. The party’s state delegates who were pledged to Biden through the primary process, as well as “superdelegates” who hold important positions within the party, are now free to vote for whatever candidate they choose, though Biden’s endorsement will likely sway many of them to now support Harris. Before Biden dropped out of the race, some of those looking for him to step aside had been pushing for an “open” nominating process in which multiple Democrats could compete for the nomination. The timing and process for that vote remain unclear now.

One option would be to hold some kind of competition in the weeks leading up to the Democratic National Convention that starts on Aug. 19. However, going into the convention with uncertainty about the nominee is far from ideal; Democrats have looked back to 1968, where a contentious Democratic National Convention led to a loss to Richard Nixon in the general election. There is also a concern that waiting until the convention to formalize the nomination may threaten the ability of Democrats to get their candidate on the ballot in Ohio, which initially had an earlier deadline to qualify. Prior to the presidential debate that started the campaign to replace Biden, Democrats had planned to hold an earlier virtual roll call to formalize the nomination before the convention. So far that plan is still on, although the dates for the virtual nominating process have not been announced. Finally, money may play an important role in determining the nomination, as Harris may be the only person who has the legal right to directly access tens of millions of dollars that have already been raised by the Biden-Harris campaign, according to election rules.

Given the unprecedented nature of changing a candidate this far into the process after a decisive primary season, the details of the process ahead will likely be made up as they go along. If Harris continues to gain key endorsements in the days ahead, she could solidify her position as the de facto nominee; in that case, Democrats will look to make her nomination official sooner rather than later. If important Democrats like former President Barack Obama hold out or if prominent challengers express their desire to run, then Democrats may try to hold a more competitive “mini primary” season before picking a nominee.

With so many things up in the air, this week will likely prove extremely important for Harris. She could essentially seal the nomination, and even if she does not do so quite yet, she is already well on her way to a historic achievement as the first woman of color to be a major party nominee.