Sen. Dan Sullivan (R-Alaska) says that President Donald Trump would suffer political consequences if he decides to fire Attorney General Jeff Sessions, whom he has repeatedly criticized in public and behind closed doors for recusing himself from overseeing special counsel Robert Mueller’s Russia probe.

“The president has the constitutional authority to remove him. He can do it. Is it politically wise? I don’t think so,” Sullivan said Sunday on NBC’s “Meet the Press,” adding that he approves of the job Sessions is doing as attorney general.

Trump’s public feud with Sessions has gone on for more than a year. Last month, after yet another Trump tweet blasting the attorney general’s performance at the Department of Justice, Sessions fired back by issuing a statement that defended DOJ prosecutors and touted the attorney general’s “unprecedented success at effectuating the President’s agenda.”

Trump told Bloomberg News last week that Sessions will stay in his position until at least the midterm elections in November despite what he called the “illegal” Russia probe. The language he used to describe the investigation marked yet another step in his escalating war of words against Mueller.

POOL New / Reuters Attorney General Jeff Sessions, seen Friday at the U.S. Capitol as the casket of late Sen. John McCain lies in state.

It’s unclear, however, whether Trump can get a replacement for Sessions, a former Alabama senator who remains popular with his former GOP Senate colleagues, confirmed in the near future. The president’s attacks on the probe have alarmed both Democrats and Republicans, stoking fears that the president was attempting to influence the Russia investigation, which is overseen by the DOJ.

“I’m very suspect about his successor if that is the case,” Sen. Dick Durbin (D-Ill.) told reporters last week when asked about Sessions’ fate. “If it isn’t [Deputy Attorney General Rod] Rosenstein, then you’re setting up a situation where Mueller and his investigation are in jeopardy.”

Sen. Jeff Flake (R-Ariz.) similarly told reporters on Capitol Hill last week he was concerned about Trump’s escalating attacks on Sessions.

“What I’m really concerned about is not just that but the knock-on effect — the dominoes, where it goes from here,” the Arizona Republican said. “Does it go to Rod Rosenstein? To Mueller? We’ve got to let Mueller continue with his investigation.”