The second-ranking Senate Republican, John Thune, endorsed Donald Trump on Sunday as Trump continues to grow his delegate lead over rival Nikki Haley. This endorsement paves the way for a potential Trump-Biden rematch in 2024.

“The primary results in South Carolina make clear that Donald Trump will be the Republican nominee for president,” said Thune on Fox News after Trump defeated Haley in her home state by 20 points over the weekend. “The choice is clear – it’s Donald Trump or Joe Biden.”

After losing South Carolina, where she previously served as governor, Haley told supporters she would not yet bow out of the race as other challengers have done.

Trump now has 107 delegates to Haley’s 17. A candidate needs 1,215 to secure the nomination. Trump has endorsements from over half the Republican Senate and at least 132 House Republicans, including leadership.

Thune follows Senator John Barrasso, the number three Senate Republican, in backing Trump. Mitch McConnell remains the only top three Republican senator who has not endorsed Trump.

“I support Trump’s campaign to win the presidency, and will do everything to see he has a Republican Senate majority working with him,” said Thune.

“Together we must end the disastrous Biden agenda and continued lawlessness at the border. Our country cannot take another four years of Bidenomics and American weakness globally,” he added.