Kamala Harris and Donald Trump held dueling rallies Monday in the final hours before Election Day when Americans will either choose the first woman president in US history or deliver the Republican an unprecedented comeback likely to rattle the world.

With polls showing a dead heat, the candidates offered up starkly different visions as they spent their last day of campaigning in the too-close-to-call swing states that are set to tip the balance after polls close Tuesday.

Both rivals even held raucous events simultaneously in Pittsburgh, a key city in the must-win battleground of Pennsylvania, as the race went down to the wire.

“Tomorrow is election day, and the momentum is on our side,” Harris said, just before singer Katy Perry took to the stage.

Republican former president Trump, who brought members of his family up on stage, stuck to his darker rhetoric, saying Harris was “a disaster.”

“We do not have to settle for weakness, incompetence, decline, and decay. With your vote tomorrow we can fix every single problem our country faces,” he said.

Trump held rallies in North Carolina and Pennsylvania ahead of a grand finale in Grand Rapids, Michigan — the same place where he closed his 2016 and 2020 campaigns.

Democratic Vice President Harris went all-in on Pennsylvania, building up to a rally on the Philadelphia Museum of Art steps made famous in the movie “Rocky,” where she will be joined by celebrities including Lady Gaga and Oprah Winfrey.

Fresh start

Both sides say they are encouraged by the early turnout, with more than 82 million people casting ballots ahead of Election Day.

Superstar Taylor Swift, one of a series of celebrity endorsers for Harris, posted to her 283 million followers an “extremely important reminder” that Tuesday is the final chance to vote.

Joe Rogan, the host of the world’s top podcast, announced on Monday that he was endorsing Trump, days after the former president appeared on his show.

Both rivals hoped their clashing messages would boost turnout among their supporters and win over any remaining undecided voters.

Speaking earlier in Reading, Pennsylvania, Trump pursued his apocalyptic vision of a United States in decline and overwhelmed by illegal immigrants, whom he described as “savages” and “animals.”

Harris hammered home her opposition to Trump-backed abortion bans across the United States — one of her key vote-winning positions — but took an upbeat, centrist note.

With Trump, at 78, being the oldest major party nominee ever to run for US president, Harris also played on the need for change.

“America is ready for a fresh start,” Harris said in Pittsburgh. “It’s time for a new generation of leadership.”

Despite being tarred with criminal convictions and the scandal of his supporters’ violent attack on Congress four years ago after he refused to accept the results of the 2020 election, Trump goes into Election Day with major advantages.

High tension

Trump has pressed on voter concerns about the economy and illegal migration while his harsh rhetoric is nectar to his right-wing base.

His message struck home for first-time voter Ethan Wells, a 19-year-old restaurant cook in Michigan.

Biden “let a lot of illegals in, and they’ve been murdering and raping our own people,” he told AFP. “When Trump was president, nobody messed with America.”

Harris, 60, faced enormous challenges on being catapulted into the race only in July after Biden abruptly dropped out.

Yet in that short time, Biden’s previously little-noticed vice president has galvanized the Democratic Party and stirred excitement among young voters and women after nearly a decade of political headlines dominated by Trump.

“It’s kind of mind-boggling that the race is so close, because he’s a convicted felon, the way he talks to women... the tariffs, everything”, said Trish Kilby, 60, at Harris’s Philadelphia rally.

“She’s more about bringing the people together, whereas all he cares about is his top one percent,” she said.

The world is anxiously watching as the outcome will have major implications for conflicts in the Middle East and Russia’s war in Ukraine, and for tackling climate change, which Trump calls a hoax.

The most immediate fear is that US democracy will buckle if Trump loses but refuses to accept defeat, like he did four years ago when his supporters stormed the US Capitol.

With Trump having narrowly survived an assassination attempt in July and police foiling a second plot, the fears of violence are very real.

In Washington, growing numbers of businesses and office buildings are being boarded up in case of unrest.