Kamala Harris and Donald Trump launched a final frenzied campaign blitz yesterday, hitting must-win Pennsylvania on the last day of a volatile US presidential race that polls say is hurtling towards a photo finish.At his first rally of the day in North Carolina, Trump, 78, shrugged off accusations that his age and the gruelling election schedule had left him physically and mentally exhausted.“I don’t even sleep. I’ve gone through 62 days without a day off,” he said in an insult-laden 90-minute stump speech that he has delivered dozens of times in recent weeks.Harris said she was “feeling good” and gave a thumbs-up as she boarded her plane to her first event of the day in Allentown, Pennsylvania.Republican Trump has promised a “landslide” as he seeks a sensational return to the White House, while Democrat Harris said “momentum” was on the side of her bid to be America’s first woman president.But the polls suggest a deadlock nationally, and also in the seven swing states where the winner is expected to be decided.The world is anxiously watching as the outcome is set to have major implications for conflicts in the Middle East and Russia’s war in Ukraine, and for tackling climate change, which Trump has called a hoax.US democracy could also be tested as Trump is expected to reject the result if he loses, raising the prospect of political chaos, civil unrest and violence.“Donald Trump and his campaign are already telegraphing they may declare victory prematurely. We fully expect him to,” Harris spokesman Ian Sams said yesterday.“It’s a sign of weakness and concern he may lose, to sow doubt in the nonpartisan election officials.”After many dramatic twists, including two bids to kill Trump and Harris’s shock late entrance, the race is coming down to Pennsylvania, the most fought-over battleground state.Trump and Harris were to hold duelling rallies in the industrial city of Pittsburgh, highlighting how Pennsylvania is the single biggest swing state prize under the US Electoral College system, which awards influence in line with population.Harris will spend the whole day campaigning in the state, culminating in a rally in Philadelphia featuring singer Lady Gaga. Trump will travel from North Carolina on to Pennsylvania and then Michigan.Both sides say they are encouraged by early turnout, with over 78mn people having voted already, around half of the total number of ballots cast in 2020.The closeness of the 2024 White House race reflects a divided United States, as it chooses between two candidates whose visions could scarcely be more different.Former president Trump has doubled down on his dark and violent rhetoric in his pursuit of a second term which would make him the first convicted felon and the oldest major party candidate ever elected.Vice President Harris, 60, has meanwhile made an astonishing rise to the top of the Democratic ticket after President Joe Biden dropped out of the race in July.Harris is hoping rights is a key issue that can hurt Trump, especially with woman voters, while Trump has focused on migrants and the economy and dubbed political opponents the “enemy from within.”They have both been on a zig-zag tour through the swing states, with raucous rallies, podcast interviews to reach reluctant voters, and stunts such as Trump riding in a trash truck and Harris appearing on television comedy show *Saturday Night Live.In the closing days of the campaign, Trump mused to supporters that he wouldn’t mind if journalists were shot, raised baseless allegations of election fraud and dwelt in gory detail on crimes by undocumented immigrants.He repeated his regular insults of his rival yesterday, saying “she’s a low IQ individual.”“Kamala, you’re fired. Get the hell out,” he told cheering supporters.Trump said this weekend that he “shouldn’t have left” the White House after he lost his 2020 re-election bid to Biden, and then tried to overturn the results, culminating in the January 6, 2021 assault on the US Capitol.After months of building tensions, some election workers have been given panic buttons to quickly alert authorities in emergencies.The states of Oregon, Nevada and Washington, have activated the National Guard in case of trouble.Harris, after some more encouraging recent polls, told a noisy rally in Michigan on Sunday that “we have momentum — it’s on our side.”Harris also courted the large Arab-American community in Michigan that has denounced US handling of the Israeli aggression in Gaza, saying she would do “everything in my power to end the war in Gaza.”Outgoing President Biden, 81, has been notably absent from the trail since a gaffe in which he referred to Trump’s supporters as “garbage” last week.