But in interviews with CNN, several other GOP senators sidestepped questions about their political futures or made clear they were truly 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” while brushing aside questions about his thinking. Johnson, 65, said he didn’t think he had 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 party out of power typically gains seats in a president’s first midterm election, but Republicans will have to defend 20 of their Senate seats in 2022, while Democrats only have to defend 14 seats.
The three retirements were somewhat of a surprise since Portman, Burr and Toomey hover around the Senate’s average age of about 62 years old. Yet they’ve bemoaned the Senate as an increasingly divided institution without the willpower to break the partisan gridlock. As of now, there are no Democratic senators who have decided to step aside, though that could quickly change.
When asked why he would stay in the Senate, Johnson said “to be a firewall” against Democratic control of Washington.
“I’m not a fan of this place,” Johnson said of the Senate. “I think this place is horribly dysfunctional.”
Other Republican senators from competitive states sounded like they would run again, even though some wouldn’t say so explicitly.
Missouri Sen. Roy Blunt, a member of the Republican leadership, said that he has not made an “official announcement.”
“When I do, that’s when the campaign will officially start,” he added.
And as she entered the Senate subway in the Capitol, Alaska Sen. Lisa Murkowski told CNN, “I’m running.” Utah Sen. Mitt Romney then interjected, “for now,” and smiled.
A number of other senators from deep red states have not announced their new campaigns, but told CNN that they intend to run, including GOP Sens. Mike Crapo of Idaho, John Hoeven of North Dakota, Jerry Moran of Kansas and John Boozman of Arkansas.
“I am running for the border first, and reelection second,” said Louisiana Sen. John Kennedy.
While Republicans are uncertain which of their members may be the next to call it quits, the decision by Portman caught many off-guard. “He’s a big loss, a big loss for the caucus, really for the country,” Thune said 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 Gov. Ted Strickland.
“I was surprised,” Sen. Rick Scott of Florida, the chair of the National Republican Senatorial Committee, told CNN of Portman’s decision. When asked if the NRSC would get involved in the primary, Scott said: “I don’t know. I know that people have in the past, so we’ll see. It will be a new experience.”
Scott has personally urged each of his incumbents to run again but said that Republicans would keep the US Senate seat in Ohio.
“It’s another race that we’ll raise the money for and win,” he said. “We’re off and running. We’re talking to candidates, we’re recruiting candidates, we’re raising money.”
But Democrats said the GOP retirements would be a boon to their chances of keeping the Senate.
“With Ohio now joining Pennsylvania and North Carolina as another open seat liability in a major battleground state, Republicans are confronting messy and divisive primaries and a 2022 map that keeps getting harder to defend,” said Democratic Senatorial Campaign Committee spokesman Stewart Boss.
The Senate is currently split 50-50 with Vice President Kamala Harris breaking tie votes, giving Democrats control of the chamber.
Republicans recognize that their work will be cut out for them if more of their colleagues step aside.
“It certainly creates more focus on candidate recruitment,” 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’s impossible to replace.”
“But finding interesting, fascinating and exciting candidates will be our task,” Scott said.
CNN’s Aaron Pellish, Clare Foran and Jeff Zeleny contributed.