President-elect Donald Trump’s call for so-called “recess appointments” of Cabinet members and other officials is the first loyalty test that Senate Republicans are facing as they prepare to vote in their next leader later this week — and could shake up the roster of picks for the 47th president’s administration.

It’s a route that is likely more precarious and cumbersome for a GOP majority that will have 53 seats and confirm nominees with a simple majority.

On Wednesday, the incoming Senate GOP majority will elect a new leader for the first time in 18 years. The race, between Sens. John Thune, John Cornyn, and Rick Scott, intensified over the weekend as President-elect Donald Trump’s win reverberated through the caucus—and Trump’s most ardent MAGA supporters attempted to bully Republican senators into submission.