Joe Biden bows out of presidential race... what happens next?

Biden has spent the last several months accruing nearly 4,000 Democratic delegates by winning primary elections in US states and territories. Those delegates would normally vote for him to be the party's official presidential nominee at the Democratic National Convention that is set to take place August. 19-22, but the rules do not bind or force them to do so. Delegates can vote with their conscience, which means they could throw their vote to someone else. By stepping aside, Biden is effectively "releasing" his delegates, potentially sparking a competition among other Democratic candidates to become the nominee.