U.S. President Joe Biden on Saturday easily won South Carolina's Democratic primary that formally began the party's nomination process for the November presidential election, saying he is confident of defeating his predecessor Donald Trump, the clear front-runner in the Republican race.

Although the outcome was not in doubt, the primary was a significant test of the incumbent president's standing among black voters, who account for more than half of the party's electorate in the Southern state and played a crucial role in his victory in the previous election.

Despite concern about his age, the 81-year-old was heavily favored over other candidates, including Minnesota congressman Dean Phillips and self-help author Marianne Williamson.

U.S. President Joe Biden (2nd from L) delivers a speech during a campaign event in Manassas, Virginia, on Jan. 23, 2024. (Kyodo) ==Kyodo

"The people of South Carolina have spoken again and I have no doubt that you have set us on the path to winning the presidency again -- and making Donald Trump a loser -- again," Biden said in a statement after major U.S. media outlets reported his overwhelming victory based on their projections.

As of about 11 p.m., with nearly 100 percent of the estimated votes counted, Biden had 96.2 percent, compared with 2.1 percent for Williamson and 1.7 percent for Phillips, according to The Associated Press.

Up for grabs were 55 delegates, with Biden securing all of them, it said.

For Biden to win reelection in a potential rematch against Trump on Nov. 5, strong support from nonwhite voters is essential.

But polls have shown that Biden is facing severe headwinds, with an increasing number of black Americans across the country unhappy with his performance since he took office in January 2021, feeling he has failed to improve their living conditions.

Voting trends in South Carolina were also closely watched because the state is where Biden's candidacy was resurrected in 2020 after early setbacks.

"The stakes in this election could not be higher. There are extreme and dangerous voices at work in the country -- led by Donald Trump -- who are determined to divide our nation and take us backward," Biden said. "We cannot let that happen."

In a departure from past practice, the Democratic National Committee changed its nomination calendar last year so that South Carolina would be its first official contest in 2024.

Biden and the party wanted to prioritize a state with more ethnic diversity than Iowa or New Hampshire, which had for decades held each cycle's first caucus and primary, respectively.

The primary in South Carolina was the first to award delegates to the Democratic Party's convention in August.

Republicans held their first contests as usual in Iowa and New Hampshire, dominated by white voters, with Trump winning both convincingly.

In New Hampshire, a largely symbolic Democratic primary, which did not award delegates, was held last week.

Although Biden was not on the ballot, he beat long-shot challengers Phillips and Williamson resoundingly thanks to a write-in campaign carried out by the president's supporters.

The Republican Party's primary vote in South Carolina on Feb. 24 is the next key event in its nomination calendar.

Nikki Haley, a former South Carolina governor who is now Trump's only Republican competitor, has been trailing the 77-year-old former president in polls.

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