First, Republican incumbents.
Republicans
Barrasso, John (R-WY)
Blackburn, Marsha (R-TN)
Braun, Mike (R-IN)
Cramer, Kevin (R-ND)
Cruz, Ted (R-TX)
Fischer, Deb (R-NE)
Hawley, Josh (R-MO)
Romney, Mitt (R-UT)
Scott, Rick (R-FL)
Wicker, Roger F. (R-MS)
Even if any incumbents retire, I consider all 10 seats to be SAFE Republican. In other words, Republicans are all but assured of not LOSING any seats this cycle.
Independents
King, Angus S., Jr. (I-ME)
Sanders, Bernard (I-VT)
Sinema, Kyrsten (D-AZ)
If King runs, SAFE Independent. If King retires, LEAN Democrat. If Sanders runs, SAFE Independent. If Sanders retires/runs for President, SAFE Democrat.
As for Sinema, right now, in the absence of any candidate information for either the Republican or Democratic primaries, I will start this race off as PURE TOSSUP. IF the Republicans don’t come up with a fruitcake, they should benefit from the split between Sinema and the Democratic nominee.
Democrats
Baldwin, Tammy (D-WI) - Lean Democrat
Brown, Sherrod (D-OH) - Tossup
Cantwell, Maria (D-WA) - Safe Democrat
Cardin, Benjamin L. (D-MD) - Safe Democrat
Carper, Thomas R. (D-DE) - Safe Democrat
Casey, Robert P., Jr. (D-PA) - Lean Democrat
Feinstein, Dianne (D-CA) - I believe Feinstein will retire, but Safe Democrat regardless
Gillibrand, Kirsten E. (D-NY) - Safe Democrat
Heinrich, Martin (D-NM) - Safe Democrat
Hirono, Mazie K. (D-HI) - Safe Democrat
Kaine, Tim (D-VA) - Likely Democrat
Klobuchar, Amy (D-MN) - Safe Democrat
Manchin, Joe, III (D-WV) - Likely Republican
Menendez, Robert (D-NJ) - Safe Democrat
Murphy, Christopher (D-CT) - Safe Democrat
Rosen, Jacky (D-NV) - Lean Democrat
Stabenow, Debbie (D-MI) - Safe Democrat
Tester, Jon (D-MT) - Likely Republican (Safe Republican if Tester retires)
Warren, Elizabeth (D-MA) - Safe Democrat
Whitehouse, Sheldon (D-RI) - Safe Democrat
Republicans don’t have to worry about losing any seats and can concentrate on picking up seats.
They will likely pick up Montana and West Virginia, giving them control of the Senate. I think Ohio is very winnable and possibly Wisconsin. Republicans have a possibility of redeeming themselves in Nevada and an outside shot in Pennsylvania. Arizona is a good possibility if Republicans get a decent nominee and Sinema and the Democratic nominee split the Democratic vote.
But I think it is very likely Republicans will control the Senate as a result of 2024.
Beyond simple bare control, 51 to 49, much is up to Republicans themselves and it will be entirely their own fault if they do not capitalize on this favorable cycle, just as it was entirely their own fault they crashed and burned in 2022. Nominate good candidates and they could potentially have 53 to 47 or even 54 to 46. Nominate Oz’s, Masters’ and Walker’s and they will be at the bare 51 to 49.