International: Donald Trump and Kamala Harris both predicted victory as they campaigned across Pennsylvania and other battleground states on Monday in the final, frantic day of an exceptionally close US presidential election.

The campaign has seen head-spinning twists: two assassination attempts and a felony conviction for Republican former President Trump, and Democratic Vice President Harris' surprise elevation to the top of the ticket after President Joe Biden, 81, dropped his reelection bid under pressure from his own party. More than $2.6 billion has been spent to sway voters' minds since March, according to AdImpact, an analytics firm.

But, what would happen if Trump loses- a repeat of the 2020 Capital Hill violence or just a "sorrowful" day?

Could there be unrest?

Trump has been aggressively promoting baseless claims in recent days questioning the integrity of the election. He falsely insists that he can lose only if Democrats cheat, even as polls show that the race is a true toss-up. Trump could again claim victory on election night regardless of the results, just as he did in 2020.

Such rhetoric can have serious consequences as the nation saw when Trump loyalists stormed the Capitol on January 6, 2021 in one of the darkest days in modern American history. And unfortunately, there is still a potential for further violence this election season.

The Republican National Committee will have thousands of “election integrity” poll monitors in place on Tuesday searching for any signs of fraud, which critics fear could lead to harassment of voters or election workers. In some key voting places, officials have requested the presence of sheriff deputies in addition to bulletproof glass and panic buttons that connect poll managers to a local 911 dispatcher.

If Trump is defeated, he will not accept the result: Expert

"If Trump is defeated, he will not accept the result and will do everything he can to try to prevent that count on, I think it's January 5th this year, where they're certifying the presidential electoral votes," said Paul A. Beck, Professor Emeritus and Academy Professor of Political Science at The Ohio State University, in an interview with news agency Reuters. "It's apparent, in fact, from things that have come out over the last few months and even after the 2020 contest itself, he tried to pull out all stops to try to prevent that outcome. He will do that again, but not from the kind of position of power that he had back in 2020 and 2020, early 2021," he added.

Sentiment for Trump

At the same time, Trump's allies note that he has faced two assassination attempts in recent months that raise the possibility of further threats against him. And police in Washington and other cities are preparing for the possibility of serious Election Day unrest. As always, it's worth noting that a broad coalition of top government and industry officials, many of them Republicans, found that the 2020 election was the “most secure” in American history."