Millions of Americans will vote in the midterm elections on Tuesday, with the balance of power in Congress at stake.
The entire US House of Representatives, about a third of the Senate and key state governorships are up for grabs.
President Joe Biden, a Democrat, and ex-President Donald Trump, a Republican, made their closing arguments in duelling rallies.
Mr Biden’s ability to pass laws will be stymied if Republicans take the House, as most projections expect.
Democrats currently control the White House and – by razor-thin margins – both chambers of Congress.
The party in power typically sheds an average of two dozen or so seats in the midterms, which fall midway through a president’s four years in office.
While Mr Biden himself is not up for re-election on Tuesday, midterms are often seen as a referendum on a president’s leadership.