Retired Lt. Gen. Dan “Razin” Caine, President Donald Trump‘s pick to become the highest-ranking military officer, pledged to lawmakers that, if confirmed, he would remain apolitical and provide his best advice to senior leaders.

Uniformed military officers are supposed to be loyal to the Constitution and not any political party or movement, but Trump has claimed that Caine showed support for the “Make America Great Again” movement during the president’s first term, raising concerns that he would not remain that way.