What is an open convention?

Washington — President Biden's announcement Sunday to end his 2024 reelection bid caps a chaotic few weeks in which he faced calls from more than three dozen elected Democrats to exit the presidential race due to concerns about his fitness for a second term.

Mr. Biden has thrown his support behind Vice President Kamala Harris, and key Democrats are lining up behind her to become the Democratic presidential nominee. Harris said in a statement that she intends to "earn and win" the party's nomination.

The shakeup at the top of the ticket comes just weeks before Democrats are poised to convene in Chicago for the Democratic National Convention, beginning Aug. 19. The party has long been planning a virtual roll call vote to formally nominate its presidential candidate to take on former President Donald Trump in November, and delegates and party leaders have been told it's expected to take place Aug. 1.