Biden secures Democratic nomination, setting stage for showdown with Trump

US President Joe Biden has won enough delegates to seal the Democratic Party's nomination, with a face-off against former President Donald Trump looming in what would be the first US presidential election rematch in nearly 70 years.

Biden needed 1,968 delegates to win the nomination, a number Edison Research said he passed on Tuesday night as results began to come in from the primary contest in Georgia, ahead of expected results from Mississippi, Washington state, the Northern Mariana Islands and Democrats living abroad.

Biden issued a statement after the news, taking aim at what he called Trump's "campaign of resentment, revenge, and retribution that threatens the very idea of America."

"Voters now have a choice to make about the future of this country. Are we going to stand up and defend our democracy or let others tear it down? Will we restore the right to choose and protect our freedoms or let extremists take them away?" he said.

Trump was expected to clinch the Republican Party's nomination later on Tuesday as four states held contests, including Georgia, the battleground where Trump faces charges for his efforts to overturn the state's 2020 results. He has won the Republican presidential primary in Mississippi.

The outcome is essentially predetermined, after Trump's last remaining rival for the Republican nomination, former UN Ambassador Nikki Haley, ended her presidential campaign following Trump's dominant performance last week on Super Tuesday, when he won 14 of 15 state contests.

Biden, meanwhile, faced some opposition in the Democratic primary campaign, though activists frustrated by his support for Israel's war in Gaza have convinced a sizable minority of Democrats to vote "uncommitted" in protest.

Both men have already turned their attention to the November 5 general election, holding dueling rallies in Georgia on Saturday.

In Rome, Georgia, Trump, 77, again repeated his claim that the 2020 election was fraudulent. He also attacked Biden for failing to stem the flow of migrants at the U.S. southern border, an issue he intends to keep front and center throughout the campaign, as he did in 2020.

The Biden campaign launched a more aggressive phase on Friday, announcing Biden would tour several battleground states amid a $30 million ad buy.

The campaign said it raised $10 million in the 24 hours after Biden's State of the Union speech, adding to Democrats' financial edge over Republicans.

Voters unenthusiastic

The last repeat presidential matchup took place in 1956, when Republican President Dwight Eisenhower defeated former Illinois Governor Adlai Stevenson, a Democrat, for the second time.

This year, voters have expressed little enthusiasm for a repeat of the bitter 2020 election, with Reuters/Ipsos public polls showing both Biden and Trump are unpopular with the majority of voters.

Trump's myriad charges - he faces 91 felony counts across four separate indictments - could harm his standing among the suburban, well-educated voters whose support he's historically struggled to garner.

He is scheduled to become the first former American president to go on trial in a case on March 25 in New York, where he faces charges he falsified business records to hide hush money payments to an obscene content actress.

The most serious case against him is generally thought to be the federal indictment in Washington, DC, accusing him of plotting to reverse the 2020 election. But the case is on hold after the US Supreme Court agreed to hear Trump's claim of presidential immunity, and it is unclear whether a trial can take place before Election Day.

Biden has been dogged by the perception among a majority of voters that he is too old to serve a second four-year term, though allies believe his fiery State of the Union address may serve to counter that notion.