From there, four states remained to be called as Wednesday evening approached in the US: Nevada, North Carolina, Georgia, and Pennsylvania.
For Trump to find the 53 electoral votes he needs, he would need to win Pennsylvania, plus all three other states.
But a huge Democratic vote share remained to be tallied in Philadelphia and Pittsburgh, meaning Trump could have difficulty hanging on to a narrow lead gained elsewhere in the state.
Biden has more paths to find his remaining six electoral votes. One path lies through Pennsylvania, which would net 20 votes.
Without Pennsylvania, Biden could win by winning Nevada, where he held a clear but narrow lead. A Biden victory in either of the two reddest states in the mix – Georgia or North Carolina – would almost certainly foretell wins elsewhere and a Biden victory.