Washington — Rep. Mike Collins has advanced to a runoff in the Georgia GOP primary for Senate, CBS News projects, as Republicans vie for an opportunity to take on Democratic Sen. Jon Ossoff. 

In Georgia, the top two vote-getters in the primary advance to a runoff if no candidate clears 50% of the vote. It's not clear yet who Collins will face in the runoff, which is set for June 16. Rep. Buddy Carter and former college football coach Derek Dooley remain in a tight race for second place.

A handful of Republicans have been seeking the nomination as the GOP eyes a chance at flipping a Senate seat in Georgia. With Ossoff being the sole Democrat seeking reelection in a state President Trump won in 2024, the race has been seen as a key pickup opportunity for Republicans. But a messy primary, and the inability to coalesce behind a candidate has complicated their path forward. 

Ossoff, who was unopposed in Tuesday's primary, has been in the Senate since 2021 when he delivered Democrats one of two runoff victories in Georgia, which secured their majority in the upper chamber. A formidable fundraiser, the 39-year-old has amassed a significant warchest to fight back against an inevitable GOP onslaught and improve his outlook despite the state's rightward shift during the last election. 

Two members of Congress, Collins, 58, and Carter, 68, had been gunning for the GOP nomination. Collins, the owner of a trucking business, has represented Georgia in the House since 2023, while Carter has been in Congress since 2015, after serving as mayor of Pooler, Georgia and in the Georgia General Assembly. Both men have strongly tied their campaigns to the president, although Mr. Trump hasn't endorsed a candidate in the primary. 

Dooley, 57, was also seeking the nomination. An attorney who coached football at the University of Tennessee, Dooley is the son of legendary University of Georgia football coach Vince Dooley and was endorsed by Georgia Gov. Brian Kemp, who passed up on a Senate bid himself. Dooley hasn't embraced the president as readily as the other two men, and has positioned himself as a political outsider. 

Polls showed Collins leading Carter and Dooley heading into the primary, despite his opponents' efforts to highlight allegations that Collins misused congressional funds, which is under investigation by the House Ethics Committee. Collins has denied the allegations.

Carter argued ahead of Tuesday's primary that he's the only GOP candidate who can defeat Ossoff, citing the Ethics Committee investigation into Collins and suggesting Dooley is insufficiently conservative. 

"If those two are our candidates, we lose," Carter said on "The Takeout with Major Garrett." "And the reason why is the focus is removed from Jon Ossoff's voting record, where it should be."

The prolonged GOP primary fight, with attention and resources diverted from the general election, is a boon for Ossoff, who has brought in a massive fundraising haul as the Senate's most vulnerable Democrat. Ossoff raised $14 million in the first quarter, and has more than $32 million in cash on hand.

On Monday, the Democratic Senate Majority PAC announced an initial $20 million investment in television ad reservations in the state. The Senate Leadership Fund, the leading Senate GOP super PAC, has also announced an initial $44 million advertising investment overall.

Despite Mr. Trump's 2024 victory in Georgia, the state hasn't elected a Republican to the Senate since 2016. And after a special election in Georgia in April saw a massive leftward swing, Democrats appear more confident that they can hold the seat that's critical to regaining the majority.