What is the electoral college?
When Americans take part in November's presidential election, most of them will cast a vote for either Democrat Kamala Harris or Republican Donald Trump.
But those votes don't directly determine who wins. Instead of a national race it's a state-by-state race.
Generally, states award all their electoral college votes to whoever wins the poll of ordinary voters in the state.
For example, if a candidate wins 50.1% of the vote in Texas, they are given all of the state's 40 electoral votes. A candidate who won a state by a landslide would still pick up the same number of electoral votes.
source: BBC