GOP bracing for possible wave of Senate retirements: 'What Republican hasn't thought about leaving?'
Senate Majority Leader Mitch McConnell. (CNN screenshot)

Republicans may face some new challenges winning back their Senate majority with another wave of retirements.

Pennsylvania and North Carolina are already up for grabs in 2022, when Republicans need only one seat to take back their majority, and Sen. Ron Johnson (R-WI) -- probably the most vulnerable GOP senator up for re-election -- hasn't yet decided whether to seek a third term and Sen. Rob Portman (R-OH) bowed out this week, reported Politico.

"It's harder when you have open seats than when you have incumbents up, so I hope we don't have any more," said Sen. John Cornyn (R-TX). "If they are going to retire, I think it's the right thing to do to do it early to give other people a chance to get in."

Republicans are still favored to win Ohio despite Portman's exit, but the GOP is concerned that Sen. Chuck Grassley (R-IA) might retire after seven terms or that Sen. Roy Blunt (R-MO) might also choose to leave -- something that many Republicans may have considered in recent weeks.

"After the riot and four years of [Donald] Trump, what GOP senator up in 2022 hasn't thought about leaving?" said Republican lobbyist and donor T.J. Petrizzo.