Sen. Tim Scott (R-S.C.) has officially declared himself a candidate for the GOP nomination for president, making him the latest Republican to enter a crowded field that has so far been dominated by former President Trump.

Scott filed paperwork with the Federal Election Commission on Friday, ahead of an expected formal campaign launch Monday.

Scott, who won reelection in November, is vying for the Republican presidential nomination against Trump, former U.S. ambassador to the U.N. Nikki Haley, former Arkansas Gov. Asa Hutchinson and entrepreneur Vivek Ramaswamy, among the party’s most high-profile contenders. 

Scott’s entry also makes him the second South Carolinian to wade into the race, joining Haley, the state’s former governor.

The Republican primary figures to be a crowded one; Florida Gov. Ron DeSantis is also expected to launch his campaign next week. Other Republicans widely speculated to be running but not yet officially entered include former Vice President Mike Pence, former New Jersey Gov. Chris Christie and New Hampshire Gov. Chris Sununu.

Despite the numerous challengers, recent polling has shown that Trump remains the Republican to beat in the primary; some surveys show the former president holding a 40-point over DeSantis, who regularly ranks second in hypothetical GOP primary polls. 

The first GOP presidential debate will take place in August in Milwaukee. 

Meanwhile, President Biden has officially announced that he’s running for reelection, and two Democrats have launched long-shot bids to unseat Biden — progressive Marianne Williamson and Robert F. Kennedy Jr., anti-vaccine activist and nephew to former President John F. Kennedy.