The Senate Republican Conference chair’s endorsement of the former president also officially establishes him as the most Trump-friendly GOP senior Republican in a conference that will have a new leader in the coming years. Senate Minority Whip John Thune (R-S.D.), former Whip John Cornyn (R-Texas) and Barrasso are seen within the Senate GOP as the favorites to succeed Senate Minority Leader Mitch McConnell.

Barrasso is likely to at least ascend to the whip job next year because of term limits on Thune. And his endorsement gives Trump backing from 20 of the 49 GOP senators.

McConnell has no relationship with Trump after the Jan. 6 insurrection and is neutral in the primary, though he’s said he will back the party’s nominee. He parried questions about Trump on Tuesday and said he chooses “not to get involved and comment about any of the people running for the Republican nomination.”

Thune previously endorsed Sen. Tim Scott (R-S.C.), who ended his campaign last year; Barrasso also spoke warmly of Scott when he launched his campaign last year. Now Thune, Cornyn, Senate GOP Policy Chair Joni Ernst (R-Iowa) and Conference Vice Chair Shelley Moore Capito (R-W.Va.) are all currently neutral in the Republican presidential primary.