Representative Mark Green, the chairman of the Homeland Security Committee, announced on Wednesday that he would not run for re-election, just a day after the Tennessee Republican oversaw the impeachment of Alejandro N. Mayorkas, the homeland security secretary.
Mr. Green, a deeply conservative former Army Ranger medic who was elected in 2018, said that he had accomplished what he had come to Washington to do.
“At the start of the 118th Congress, I promised my constituents to pass legislation to secure our borders and to hold Secretary Mayorkas accountable,” Mr. Green said in a statement. “Today, with the House having passed H.R. 2 and Secretary Mayorkas impeached, it is time for me to return home.”
Mr. Green, 59, is the third committee chairman who would have been eligible to lead their panel next year to say they will leave Congress at the end of the year. Also this week, Representatives Cathy McMorris Rodgers of Washington, 54, the chairwoman of the Energy and Commerce Committee, and Mike Gallagher of Wisconsin, 39, who heads the select committee on China, announced they would not run for re-election.
Taken together, they are striking decisions for relatively young members of Congress who won the gavels of powerful committees — coveted positions that lawmakers often wait years to receive — only a year ago.
“This place is so broken, and making a difference here is just — you know, just it feels like a lot of something for nothing,” Mr. Green said in an interview with Axios.
In his statement, he hinted without elaborating that he would not leave public service, saying that he would “continue serving this country — but in a new capacity.”
Mr. Green, a member of the ultraconservative Freedom Caucus, served as a flight surgeon during the mission that captured Saddam Hussein, and later wrote about his experience interviewing the Iraqi leader in his book “A Night with Saddam.” President Donald J. Trump nominated Mr. Green in 2017, when he was a state senator, to serve as Army secretary, but he withdrew after lawmakers in both parties expressed concern about a series of anti-transgender comments he had made.
As chairman of the Homeland Security Committee, Mr. Green led efforts to impeach Mr. Mayorkas, making him the first sitting Cabinet secretary ever to be charged by the House. That put the secretary in the company of past presidents and administration officials who had been impeached on allegations of personal corruption and other wrongdoing.
But the charges against Mr. Mayorkas broke with precedent by failing to identify any such offense, instead effectively declaring the policy choices he has carried out to be a constitutional crime.
Former homeland security secretaries and many constitutional law experts — including conservatives — have said the charges do not rise to the level of a high crime or misdemeanor, the constitutional standard for impeachment.
The initial attempt at impeaching Mr. Mayorkas also broke new ground last week, when the House defeated the articles of impeachment Mr. Green’s panel had approved in a stunning scene on the floor, as Republicans fell a vote short of cobbling together a majority because of defections and absences.
The House tried again on Tuesday, and prevailed by a single vote.
Karoun Demirjian contributed reporting.