President Joe Biden and former President Donald Trump held rival rallies as the election to reshape Congress entered its final day of campaigning.
Mr. Biden and Mr. Trump made last-minute appeals to voters in New York and Florida, respectively.
Momentum has recently shifted to Republicans, who are trying to wrestle Democratic control of both chambers.
He is the favorite to win control of the House of Representatives, but polls show the Senate is a toss-up.
Winning one chamber would severely hamper President Biden’s legislative agenda.
In the final day of campaigning on Monday, his party is also facing losses in parts of the country where Democrats typically do well.
He spoke at a rally in New York on Sunday to support Gov. Cathy Hoechl, who is facing an unexpectedly strong challenge from Trump-backed Republican Lee Zilden.
He got last-minute help from some Democratic star names — former President Bill Clinton, Vice President Kamala Harris and former Secretary of State Hillary Clinton.
In his speech, Mr. Biden called the election an “inflection point” that will define the next 20 years. He told voters at Sarah Lawrence College that they were choosing between two “fundamentally different visions of America.”
Meanwhile, his White House predecessor, Mr Trump, was in Miami where he spoke for more than an hour, hammering Democrats for leading the country to “communism”.
“Democrats want to turn America into communist Cuba or socialist Venezuela,” Mr Trump told the audience.
“To every Hispanic American in Florida and across the country, we welcome you into our [Republican] Party with open arms,” ​​he continued.
