Senate Republicans are facing a brain drain as some of the caucus’s biggest dealmakers prepare to head for the exits. 

Sen. Roy Blunt’s (R-Mo.) announcement this week that he will not run for reelection is the latest blow for the GOP’s governing wing of the Senate, a coalition of policy wonks and bipartisan-minded institutionalists who have been at the center of the biggest legislative accomplishments. 

Though the membership of Congress is always in flux — a third of the Senate is up every two years and the full House every two — the turnover amongst some of the most successful GOP negotiators is particularly acute. 

“There’s a lot of experience, a lot of knowledge leaving. ... It's a loss of a lot of institutional memory,” said Sen. John Cornyn (R-Texas), an adviser to Senate Minority Leader Mitch McConnell (R-Ky.).

In addition to Blunt, Sens. Richard Shelby (R-Ala.), Rob Portman (R-Ohio), Pat Toomey (R-Pa.) and Richard Burr (R-N.C.) are all expected to retire at the end of 2022. 

Each holds a top GOP committee spot. Blunt and Shelby, in particular, are known for their ability to craft deals; Portman and Toomey are well versed in policy and Burr has earned the respect of Democrats for his work as Intelligence Committee chairman. 

Other GOP senators seen as dealmakers have also left the Senate in recent years. 

Former Sens. Lamar Alexander (R-Tenn.) and Pat Roberts (R-Kan.) — two GOP chairmen with big bipartisan accomplishments — retired at the end of 2020. Former Sen. Johnny Isakson (R-Ga.) stepped down in 2019 due to health reasons. 

The end of 2018 saw the departure of former Sens. Orrin Hatch (R-Utah), then the chairman of the Finance Committee; Bob Corker (R-Tenn.), then the chairman of the Foreign Relations Committee; and Jeff Flake (R-Ariz.), a conservative who was willing to buck his party. Former Sen. John McCain (R-Ariz.) died in 2018. 

Asked about the trail of departures, Sen. Lisa Murkowski (R-Alaska) interjected “all of the institutionalists?” 

“I think about just the years of legislating that they have brought to these discussions, it’s going to be a real loss. A loss for the institution really,” Murkowski said. 

“Over the years, Congress has changed and we’ve seen different leaders rise, perform and leave. … But it just seems like, it seems like, we're losing so much of that substantive tenure in a very short period,” she added. 

It’s far from certain the current exits will be the only ones for Senate Republicans. Sen. Chuck Grassley (Iowa), the top Republican on the Judiciary Committee and the panel's former chairman, isn’t expected to make a decision about running for another term until the fall. Murkowski — who Trump has threatened to campaign against — also hasn’t said if she will run for reelection. 

Murkowski, asked if she had made a decision on 2022, said, “I have to do it before 2022.” 

The departures are being watched closely by Democrats. 

“These are people I’ve worked with for years. They harken back to an era where there was bipartisan cooperation so I’m worried about their absence,” said Sen. Dick Durbin (D-Ill.). 

Asked if he had seen the same interest in bipartisanship from newer members, Durbin replied, “not yet.”

The changing of the guard comes as many GOP institutionalists are replaced with Republicans more in the mold of former President Trump.

GovTrack, a congressional analysis website, ranked Sen. Marsha Blackburn (R-Tenn.) as the senator most ideologically to the right in 2019. Her predecessor, Corker, was ranked 47 in 2018. 

Sen. Tommy Tuberville (R-Ala.), who replaced former Sen. Doug Jones (D-Ala.), has a 100 percent Trump score according to FiveThirtyEight. Shelby, while still a typical Trump vote, was at 90 percent. Former Sen. Martha McSally (R-Ariz.) voted with Trump 94.9 percent of the time; McCain, whose seat she was appointed to, was at 83 percent. 

Republicans only need a net gain of one seat to win back the majority next year. But they are defending 20 seats in 2022, including two in states won by Biden: Pennsylvania, where Toomey is retiring, and Wisconsin, where Sen. Ron Johnson (R) hasn’t made a decision but suggested recently his preference is to leave after 2022. 

Open seats could attract Trump loyalists, which could tilt the Senate GOP further toward Trump if they are elected.

Rep. Mo Brooks (R-Ala.), the House firebrand who supported efforts to overturn the election results, has indicated that he’s looking at running for Shelby’s seat. Rep. Jason Smith (R-Mo.) — who votes with Trump 94 percent of the time according to FiveThirtyEight — also said Tuesday that he’s considering a run for Blunt’s seat. 

“I would definitely compare my record for working class families and my conservative credentials against anyone that's named. ... So, I am considering it,” he said. 

It’s possible other senators will step into the shoes of the dealmakers. GOP senators who have been willing to cut deals include Murkowski, Sen. Susan Collins (Maine), Sen. Marco Rubio (Fla.) and others. 

“I think some of that is because of their experience, they have maybe a more extensive and nuanced understanding of not just the short-term but long-term consequences of doing things,” Cornyn said. “My experience is if we’ve got 50 others, people do step up.” 

Blunt, asked on Tuesday about senators leaving from the institutionalist wing of the party, questioned if that was “fair to the members that are staying,” predicting that senators who might be more ideological now would step up to fill any void. 

Speaking to reporters in Missouri on Monday, Blunt warned his potential successors of drawing hard lines on what they would never agree to. 

“I think the country in the last decade or so has sort of fallen off the edge with too many politicians saying, ‘If you vote for me I'll never compromise on anything,’ ” Blunt said. “The failure to do that — that's a philosophy that particularly does not work in a democracy.”