But in interviews with CNN, several other Republican senators avoided questions about their political future or made it clear that they were really undecided about running again, including Sens. John Thune of South Dakota, Ron Johnson of Wisconsin, Chuck Grassley of Iowa and Richard Shelby of Alabama.
Thune, 60, said he would make his announcement “at some point in the future”, leaving aside questions about his thinking. Johnson, 65, said he didn’t think he needed to decide “for a while”. Grassley, 87, said he would make his announcement in “several months”. Shelby, 86, said, “I’ll let you know.”
The out-of-power party usually wins seats in a president’s first half-term election, but Republicans will have to defend 20 of their seats in the Senate in 2022, while Democrats will only have to defend 14 seats.
The three pensions were somewhat of a surprise, as Portman, Burr and Toomey revolve around the Senate average age of about 62. Still, they lamented the Senate as an increasingly divided institution, without the willpower to break the party’s impasse. At the moment, there are no Democratic senators who have decided to step aside, although that could change quickly.
When asked why he would remain in the Senate, Johnson said he was “a firewall” against Washington’s Democratic control.
“I’m not a fan of this place,” said Johnson of the Senate. “I think this place is terribly dysfunctional.”
Other Republican senators from competitive states sounded like they were going to run again, although some did not say so explicitly.
Missouri Sen. Roy Blunt, a member of the Republican leadership, said he did not make an “official announcement”.
“When I do, the campaign will officially begin,” he added.
And when she got on the Senate subway on Capitol Hill, Alaska Senator Lisa Murkowski told CNN, “I’m running.” Utah Senator Mitt Romney then interrupted, “for now”, and smiled.
Several other senators from deep red states have not announced their new campaigns, but have told CNN that they intend to run, including the GOP Sens. Mike Crapo of Idaho, John Hoeven of North Dakota, Jerry Moran of Kansas and John Boozman of Arkansas.
“I’m running for the border first and then for re-election,” said Louisiana Sen. John Kennedy.
Although Republicans are unsure which of their members will be the next to give up, Portman’s decision caught many off guard. “He’s a big loss, a big loss for the caucus, really for the country,” said Thune of Portman.
The Ohio Republican also had a unique connection to his state, winning his last race in 2016 by 20 points against former Democratic governor Ted Strickland.
“I was surprised,” Florida Senator Rick Scott, chairman of the National Republican Senatorial Committee, told CNN about Portman’s decision. When asked if the NRSC would get involved in the primaries, Scott said, “I don’t know. I know people have been involved in the past, so we’ll see. It will be a new experience.”
Scott personally asked each of its occupants to run again, but said Republicans would keep the US Senate seat in Ohio.
“It is another race for which we are going to raise money and win,” he said. “We are ready and running. We are talking to candidates, we are recruiting candidates, we are raising money.”
But Democrats said Republican Party pensions would be a boon to their chances of maintaining the Senate.
“With Ohio now joining Pennsylvania and North Carolina as another open responsibility in a major battle state, Republicans are facing confusing and divisive primaries and a 2022 map that is becoming increasingly difficult to defend,” said Stewart Boss, spokesman for the Democratic Senate Campaign Committee.
The Senate is currently divided by 50-50 with Vice President Kamala Harris breaking the vote, giving Democrats control of the chamber.
Republicans recognize that their work will be harmed if more of their colleagues leave.
“It certainly creates more focus on recruiting candidates,” said Sen. Tim Scott, a Republican who is running for reelection in South Carolina next year. Retirements, he said, amount to “a loss of institutional knowledge on our side that is impossible to replace”.
“But finding interesting, fascinating and exciting candidates will be our task,” said Scott.
CNN’s Aaron Pellish, Clare Foran and Jeff Zeleny contributed.