Sen. Tim Scott of South Carolina filed paperwork Friday to run for president in 2024, officially throwing his hat into a growing Republican primary lineup that former President Donald Trump has so far led.

Scott is expected to announce his presidential campaign on Monday morning in North Charleston. He made it official Friday morning when he filed a statement of candidacy with the Federal Election Commission designating a principal campaign committee for a presidential bid.

The 57-year-old lawmaker, who is the Senate's sole Black Republican, arrives as an underdog in the primary. He has polled in the low single digits in surveys of the potential field even after launching an exploratory committee last month.

Scott's campaign didn't comment on the filing, which allows the senator's campaign to start placing TV and radio ads as part of a massive $6 million buy for Iowa and New Hampshire. The ads are expected to begin running next Wednesday.

Scott's brand of politics, marked by optimism and gestures toward stitching a divided nation back together, has been mostly absent from the Republican presidential conversation.

Trump, the clear polling frontrunner, is a regular source of divisive rhetoric that describes the U.S. under President Joe Biden as something like a dystopia. Florida Gov. Ron DeSantis, a top contender who is expected to announce his own presidential run next week, rose to national prominence by engaging in polarizing political fights over hot-button social issues.

Scott has been critical of Biden, but he has also homed in on a message of unity that in some ways echoes the Democratic president's messaging in the 2020 election. He announced his presidential exploratory campaign on the day marking the start of the Civil War, underlining that America's soul in that contest "was put to the test, and we prevailed."

"I will never back down in defense of the conservative values that makes America exceptional," he said in a video released on that day.

Scott's fellow South Carolina Republican, former Gov. Nikki Haley, has been running for president since February.

Democrats quickly sought to tie Scott with Trump.

"Even before he refused to name a policy difference with Trump, Scott was a fierce advocate of the MAGA agenda – supporting national abortion bans and championing plans to end Medicare and Social Security as we know them," Democratic National Committee Chair Jaime Harrison, who once ran for one of South Carolina's U.S. Senate seats, said in a statement Friday. "There's no question that special interests are celebrating as Tim Scott throws his hat into the 2024 race for the MAGA base."