By Gram Slattery

WASHINGTON Tim Scott, the only Black Republican in the U.S. Senate, is set to kick off his 2024 presidential campaign on Monday, betting that his optimistic message will sell in a party in which many voters are still firmly behind former President Donald Trump.

While Scott formally acknowledged his candidacy in a filing with the federal election regulator on Friday, his speech to supporters in his hometown of North Charleston, South Carolina, on Monday is expected to mark the start of campaigning.

With only 1% of support among registered Republicans according to Reuters/Ipsos polling, Scott faces an uphill battle in his bid to win the Republican nomination to take on Democratic President Joe Biden next year.

But with the possible exception of former U.S. ambassador to the United Nations and fellow South Carolina native Nikki Haley, Scott will be the highest-profile Republican to formally announce his intention to take on Trump - the current front-runner - for the party's nomination.

Some 49% of Republicans plan to vote for Trump, according to Reuters/Ipsos polling.

Trump's closest rival, Florida Governor Ron DeSantis, will jump into the race in the coming days, according to sources with knowledge of his plans.

Scott stands out in part due to his relentless optimism and his calls for unity. He often points to his own impoverished upbringing as proof that America remains a land of opportunity.

Still, it remains to be seen if a significant number of Republicans find his message appealing.

Many Republicans appear hungry for a bruising fight with Democrats this election. That is particularly true after New York prosecutors indicted Trump in March for allegedly falsifying documents to cover up hush money paid to a porn star. Most Republicans consider those charges politically motivated.

Scott, 57, is likely to be the only Republican senator to jump into the race, an oddity given that the Senate has traditionally been a staging ground for Republicans with presidential aspirations.

Among his political assets are his popularity in South Carolina, which plays a key role in the Republican race. It is the third state in the nation to hold a nominating contest in the state-by-state battle to determine a presidential nominee.

He is also a favorite among donors. Among his major backers is billionaire Larry Ellison, the co-founder of Oracle.

(Reporting by Gram Slattery; Editing by Will Dunham and Scott Malone)