Sen. Richard Shelby, R-Ala., on Monday announced he would not run for reelection in 2022. The decision comes as the Republican party continues to face division in the post-Trump era.

Shelby is 86 years old and has served in the Senate for 42 years. He has consistently won his seat by a wide margin in a traditionally red state.

In a statement, Shelby said he will not be seeking other offices, choosing retirement.

“For everything, there is a season,” he said. “I am grateful to the people of Alabama who have put their trust in me for more than forty years. I have been fortunate to serve in the U.S. Senate longer than any other Alabamian."

He rose to become chair of the Appropriations, Rules, Banking and Intelligence Committees.

While his seat isn’t expected to hold for Republicans, there will be substantial competition in the primary to choose a successor. Among the potential candidates, Rep. Mo Brooks looms large.

In a statement, Brooks told CNN he would either be running for reelection or going after Shelby’s seat. He said his prospects have been buoyed by Democratic attempts to censure him for a speech he made at the rally proceeding the Capitol riots.

“The last three months of scurrilous & palpable false attacks on me by socialist Democrats and their fake news media allies have been a wonderful blessing because they have sent my state-wide name I.D. and Republican primary support through the roof," Brooks said.

Christopher Dodd (D-CT) (L) confers with Sen. Richard Shelby (R-AL)
Chairman of the Senate Banking, Housing and Urban Affairs Committee Christopher Dodd (D-CT) (L)confers with Sen. Richard Shelby (R-AL). Today the Senate opened the way to a vote on extending the Bush-era tax cuts. Reuters

Even with Alabama likely a lock, Republican prospects of retaking the House or Senate in 2022 look grim. Shelby is the fourth Republican Senator to retire, meaning a full fifth of the seats Republicans have to defend will lack an incumbent. Republicans face lackluster favorable ratings with talk of Donald Trump potentially starting his own party.

The Democrats' field, meanwhile, lacks vulnerabilities in both the House and Senate.

Meanwhile, two Republican senators have not announced whether or not they will run: Iowa's Chuck Grassley and Wisconsin's Ron Johnson.

Johnson has been unclear about his plans, suggesting he could run for reelection, run for governor, or just retire. Grassley will be 89 years old in the 2022 race, which if he won would keep him in office until he’s 95.

There have also been two Republicans who have died from COVID-19. On Sunday, Rep. Ron Wright of Texas died from COVID complications and Rep.-elect Luke Letlow of Louisiana died on Dec. 29.