The candidate who gets 270 electoral votes will be the one who wins the presidency, and the fate of Harris and Trump will likely depend on the outcomes in the seven battleground states: Arizona, Nevada, Georgia, Michigan, Wisconsin, Nevada and North Carolina. .

Here are some ways for Harris to reach 270 that seem most plausible given past election results:

Mr. Biden won six of the battleground states in 2020: Arizona, Nevada, Georgia, Michigan, Wisconsin and Pennsylvania. He won a total of 306 electoral votes. On Election Day 2024, the polls are close even in these states.

If Harris wins Michigan, Pennsylvania and Wisconsin, the “blue wall” of the Midwest, Mr. Biden argues in 2020, and earns three of Maine’s four electoral votes, but she loses Arizona, Nevada and Georgia, Harris would not deliver the White House.

Under this hypothesis, Trump would also hold on to all the states he won in 2020 and four of Nebraska’s five electoral votes, as he did four years ago.

That scenario would put Harris at 269 electoral votes — one that would fail to keep the White House under Democratic control. To get to 270, Harris would have to win a congressional district in Nebraska, which includes the city of Omaha. The state awards a portion of its electoral votes by congressional district, and wins The Omaha-based district of Nebraska that captured Mr. Biden in 2020 but detained Trump in 2016 would make Harris president.

— Hunter Woodall and Olivia Rinaldi