Election Day live updates: Polls are now closed in half the country as results come in: NPR

Voters line up to vote at Lowrey School in Dearborn, Michigan, on Tuesday.

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This article originally appeared as part of NPR's live coverage of the 2024 election. For more election coverage from NPR Network, visit our live updates page.

As Americans cast their votes in this historic election, some votes are – as usual – more important than others.

There are seven states widely considered competitive in this election: the blue wall states of Michigan, Wisconsin and Pennsylvania, and the Sun Belt states of Nevada, Arizona, North Carolina and Georgia.

The United States elects presidents not by popular vote, but by the unique Electoral College. In the vast majority of states, this means that the winner of a state gets all the voters in that state, regardless of the margin of victory.

Marie Guenther votes with her son at the Bay View Library on October 20, 2020 in Milwaukee, Wisconsin, which was considered a battleground state in the 2020 presidential election.

Two maps of the USA with the states sized according to their number of votes in the Electoral College. Each is in color and shows a combination of results that could lead to a Harris or Trump victory.

What this means in practice is that voters in these swing states – states where the race between candidates is very close and could be swayed one way or another – have a disproportionate influence on the national results.

The list of swing states is anything but static: It changes as voting patterns change. Florida, for example, was a major swing state for many years, but has become increasingly Republican and lost that status. The same goes for Ohio. Meanwhile, Georgia was once reliably in the red, but is now in play for the Democrats.