Johnson’s decision, in a critical swing state won by President Joe Biden, is one of several inflection points that could reshape the battle for the Senate majority in 2022. In total, five senators haven’t yet made up their minds on whether to retire: four Republicans and just one Democrat, Patrick Leahy of Vermont.

The GOP is already defending five Senate seats opened up by retirements — two in the battlegrounds of Pennsylvania and North Carolina and three in GOP strongholds Ohio, Alabama and Missouri. Although Republicans are increasingly favored to win the House next year, further retirements would undoubtedly complicate their path back to power in the Senate.

Democrats say the hesitation will hurt Republicans next November.

“I would think that they would make a decision before this time. Because it takes time to put a campaign together. It’s unusual,” said Michigan Sen. Gary Peters, who chairs the Democrats’ campaign arm and just won a competitive reelection bid himself. “These are big races, and they’re going to be intense for everyone who is running. And delay usually puts you at a disadvantage.”