US: Coast-to-coast Super Tuesday contests poised to move Biden, Trump closer to November rematch

US President Joe Biden and former president Donald Trump are poised to move much closer to winning their party's nominations during the biggest day of the primary campaign on Tuesday, setting up a historic rematch that many voters would rather not endure.

Super Tuesday elections are being held in 16 states and one territory – from Alaska and California to Vermont and Virginia. Hundreds of delegates are at stake, the biggest haul for either party on any single day.

While much of the focus is on the presidential race, there are also important down-ballot contests.

California voters will choose candidates who will compete to fill the Senate seat long held by Dianne Feinstein. The governor's race will take shape in North Carolina, a state that both parties are fiercely contesting ahead of November. And in Los Angeles, a progressive prosecutor is attempting to fend off an intense reelection challenge in a race that could serve as a barometer of the politics of crime.

But the premier races center on Biden and Trump. And in a dramatic departure from past Super Tuesdays, both the Democratic and Republican contests are effectively sealed this year.

The two men have easily repelled challengers in the opening rounds of the campaign and are in full command of their bids – despite polls making it clear that voters don't want this year's general election to be identical to the 2020 race.

A new AP-NORC Center for Public Affairs Research poll finds a majority of Americans don't think either Biden or Trump has the necessary mental acuity for the job.

"Both of them failed, in my opinion, to unify this country," said Brian Hadley, 66, of Raleigh, North Carolina.

Neither Trump nor Biden will be able to formally clinch their party's nominations on Super Tuesday. The earliest either can become his party's presumptive nominee is 12 March for Trump and 19 March for Biden.

The final days before Tuesday demonstrated the unique nature of this year’s campaign. Rather than barnstorming the states holding primaries, Biden and Trump held rival events last week along the US-Mexico border, each seeking to gain an advantage in the increasingly fraught immigration debate.

After the Supreme Court ruled 9–0 on Monday to restore Trump to primary ballots following attempts to ban him for his role in helping spark the Capitol riot, Trump pointed to the 91 criminal counts against him to accuse Biden of weaponising the courts.

"Fight your fight yourself," Trump said. "Don't use prosecutors and judges to go after your opponent."

Biden delivers the State of the Union address on Thursday, then will campaign in the key swing states of Pennsylvania and Georgia.

The president will defend policies responsible for "record job creation, the strongest economy in the world, increased wages and household wealth, and lower prescription drug and energy costs", White House communications director Ben LaBolt said in a statement.

That's in contrast, LaBolt continued, to Trump's "Make America Great Again" movement, which consists of "rewarding billionaires and corporations with tax breaks, taking away rights and freedoms, and undermining our democracy".

Biden's campaign called extra attention to Trump's most provocative utterances on the campaign trail, like when he evoked Adolf Hitler in suggesting that immigrants were "poisoning the blood" of the US and said he'd seek to serve as a dictator during his first day back in the White House.

Trump recently told a gala for Black conservatives that he believed African Americans empathised with his four criminal indictments, drawing a sharp rebuke from the Biden campaign and top Democrats around the country for comparing personal legal struggles to the historical injustices Black people have faced in the US.

Trump has nonetheless already vanquished more than a dozen major Republican challengers and now has only one left: Nikki Haley, the former president's onetime UN ambassador who was also twice elected governor of her home state of South Carolina.

Haley has hopscotched across the country, visiting at least one Super Tuesday state almost daily for more than a week and arguing that her base of support – while far smaller than Trump's – suggests the former president will lose to Biden.

"We can do better than two 80-year-old candidates for president," Haley said at a rally Monday in the Houston suburbs.

Haley has maintained strong fundraising and notched her first primary victory over the weekend in Washington, DC, a Democrat-run city with few registered Republicans.

Trump tried to turn that victory into a loss for the overall campaign, scoffing that she had been "crowned queen of the swamp".

Though Trump has dominated the early Republican primary calendar, his victories have shown vulnerabilities with some influential voter blocs, especially in college towns like Hanover, New Hampshire, home to Dartmouth College, or Ann Arbor, where the University of Michigan is located, as well as in some areas with high concentrations of independents.

Still, Haley winning any of Super Tuesday's contests would take an upset. And a Trump sweep would only intensify pressure on her to leave the race.

Biden has his own problems, including low approval ratings and polls suggesting that many Americans, even a majority of Democrats, don't want to see the 81-year-old running again.

The president won easily in the Michigan primary last week. However, more than 100,000 people voted "uncommitted" after a campaign organised by activists who disapprove of the president's handling of Israel's war on Gaza.

Allies of the "uncommitted" vote are pushing similar protest votes elsewhere. One to watch is Minnesota, which has a significant population of Muslims, including in its Somali American community, and liberals disaffected with Biden. Governor Tim Walz, a Biden ally, told The Associated Press last week that he expected some votes for "uncommitted" on Tuesday.

While Biden is the oldest president in US history, his reelection campaign argues that skeptics will come around once it is clear it'll be him or Trump in November. Trump is 77 and faces his own questions about age that have been exacerbated by flubs like over the weekend when he mistakenly suggested he was running against former president Barack Obama.

That hasn't shaken Trump's ardent supporters' faith in him.

"Trump would eat him up," Ken Ballos, a retired police officer who attended a weekend Trump rally in Virginia, said of a November rematch, adding that Biden "would look like a fool up there".