The battle to replace Senate Republican leader Mitch McConnell has morphed into a two-person race between Minority Whip John Thune of South Dakota and Texas Sen. John Cornyn. 

Senate Republican Conference Chair John Barrasso of Wyoming, the third-ranking GOP senator, announced Tuesday that he will not seek to be Mr. McConnell’s successor but will instead run for the party’s No. 2 position as whip. 

“I have had time to reflect on how I might best serve you, our entire Republican Conference, and our country,” Mr. Barrasso wrote to Senate Republicans in a letter, citing the recent passing of his wife Bobbi.

Mr. Thune and Mr. Cornyn, who’s previously held several leadership positions, are the early favorites, though other candidates from the party’s more conservative faction could still enter the race. 

Sen. Joni Ernst of Iowa, the fourth-ranking Republican, remains undecided. 

Sen. Tom Cotton of Arkansas is seeking Mr. Barrasso’s spot as Republican Conference chair. 

Mr. McConnell of Kentucky will retire from his 17-year stint as Senate GOP leader after the November election, but will serve the remainder of his term that ends in January 2027.

• Ramsey Touchberry can be reached at rtouchberry@washingtontimes.com.