Responding to a June tweet from the president that alleged that he had seen TV anchor Mika Brzezinski bleeding as a result of cosmetic surgery, Sasse tweeted, “Please just stop. This isn’t normal and it’s beneath the dignity of your office.”

In October, Sasse released a statement wondering whether Trump was “recanting” his oath to protect the Constitution, in particular the First Amendment, after the president said it was “disgusting the press is able to write whatever they want.”

Some Trump critics view Sasse with skepticism, saying he has been all talk and little action in terms of dissent. They note he has rarely bucked the administration’s line when it comes to actual votes, for example.