 At a political party's national convention, delegates decide on a presidential nominee. Delegates are people, and they have opinions on who should be president. But they can't just vote for whomever they want. The rules say most delegates are bound to vote for whatever candidate the voters have chosen in their state or district. A small number of delegates are able to vote for whomever they want. In the Democratic Party, these are called superdelegates. In the first round of voting, most delegates are still bound to a candidate. In later rounds, most of the delegates become unbound and can vote for their preferred candidate. Once a candidate receives a majority of delegate votes, they are declared the winner. Soon after, each nominee chooses a running mate and campaigns around the country in preparation for the general election in early November.