Sinema’s Defection Gives Democrats More Heartburn Over the 2024 Senate Map

In Pennsylvania, Republicans are hoping that David McCormick, who lost narrowly to Dr. Mehmet Oz in the primary this year, will challenge Senator Bob Casey in 2024. Democrats saw McCormick, a former hedge fund executive with deep pockets and roots in Pittsburgh, as the more formidable potential opponent, and subtly tried to help Oz. McCormick is planning to release a book in March, “Superpower in Peril: A Battle Plan to Renew America,” that appears aimed at positioning him more squarely as a China hawk, shoring up a point of vulnerability that hurt him this year.

“I’d be shocked at this point if he doesn’t run,” said Josh Novotney, a former aide to Senator Pat Toomey and a partner at SBL Strategies, a lobbying firm in Pennsylvania. But Novotney cautioned that if Trump were the nominee, it could doom Republicans’ chances of defeating Casey. In the 2022 Senate race, Oz was weighed down by Trump and by Doug Mastriano, the Republican nominee for governor, whose hard-line stances on abortion and embrace of election denialism repelled swing voters.

Democratic senators are also up for re-election in Michigan and Wisconsin, where their chances look brighter. In 2018, Baldwin crushed her Republican opponent, Leah Vukmir, by nearly 11 points, while in Michigan, Senator Debbie Stabenow cruised to victory over John James, who opted to run for a House seat rather than face Stabenow again. This year, Gov. Gretchen Whitmer won re-election easily, while Democrats took full control of the State Legislature for the first time in 40 years.

Sinema’s defection undeniably makes Democrats’ path more complicated. She has not said she is running, though many political observers suspect her decision to switch parties had to do with worries she would lose a Democratic primary. Neither of the two most prominent Democrats weighing a run, Representatives Ruben Gallego and Greg Stanton, has officially entered the race, however.

Republicans in Arizona could nominate someone on the far right, such as Sheriff Mark Lamb, or a moderate like Karrin Taylor Robson, a lawyer who lost to Kari Lake in this year’s primary for governor. So although most analysts assume that a three-way race would help Republicans, there are too many variables to draw any firm conclusions — including whether there will even be a three-way race.

For now, Democrats are philosophical about the 2024 landscape. “Every election,” Poersch said, “you’re testing: Have the rules changed, or are we playing by the same old rules?”