Senator Richard Shelby of Alabama announced on Monday he won't be seeking re-election in 2022, the fourth Republican senator to do so recently.
“I am grateful to the people of Alabama who have put their trust in me for more than forty years," Mr Shelby, who was first elected in 1986 as a conservative Democrat before switching parties, wrote in a statement. "I have been fortunate to serve in the US Senate longer than any other Alabamian."
His exit means there were be an opening for a Republican on the powerful Appropriations Committee, which helps direct federal funds.
“It’s going to cost Alabama a trillion dollars to not have Shelby in the US Senate,” GOP consultant Brent Buchanan told Roll Call about the 86-year-old senator, who helped direct government dollars towards aerospace and other important industries in Alabama.
GOP senators Rob Portman of Ohio, Richard Burr of North Carolina, and Pat Toomey of Pennsylvania have all also announced they won't be competing for another term in the next Senate elections, meaning Republicans will compete among themselves to fill the seats, and Democrats will try to flip them and cement their slim majority in Congress.
It's unlikely a Democrat will be able to fill Mr Shelby's post, representing deeply conservative Alabama. Democrat Doug Jones briefly represented Alabama after beating Roy Moore, a Republican former Alabama Supreme Court justice accused of sexual assault and molestation, in a special election to replace Jeff Sessions after he resigned to join the Trump administration, but the seat went back to Republican control during the 2020 election.
Announcing his retirement in late January, Mr Portman cited "partisan gridlock" as one of the things that encouraged him to go.
“I don’t think any Senate office has been more successful in getting things done, but honestly, it has gotten harder and harder to break through the partisan gridlock and make progress on substantive policy, and that has contributed to my decision," he wrote in a statement at the time. “We live in an increasingly polarised country where members of both parties are being pushed further to the right and further to the left, and that means too few people who are actively looking to find common ground."
Mr Burr announced he wouldn't seek another term during his 2016 Senate race, and Mr Toomey made his announcement last October.
Senator Toomey was one of just five of 50 Republicans to vote down a January measure which would've declared the upcoming impeachment trial unconstitutional.
"In my view, the text and context of the Constitution, the meaning of the term 'impeachment' to the founders, and the most relevant precedents indicate that it is constitutionally permissible for the Senate to consider the impeachment of President Trump," he said in a statement afterward.