The size of Republicans' Senate majority is very important
We already know Republicans are going to control the Senate next year — so why are we still tracking any races there? Because the exact number of seats Republicans win is super important.
So far, the GOP has clinched at least 52 Senate seats. By recent standards, that's a downright huge majority (remember, the Senate was tied 50-50 in 2021-22 and Democrats had just a 51-49 majority in 2023-24), but Trump and whoever the next Senate majority leader is would probably prefer more of a cushion. That's because there are a number of Republican senators — namely, Susan Collins, Lisa Murkowski, Todd Young and Bill Cassidy — who are no fans of Trump and might not be an automatic vote for his agenda or appointees. If Republicans only win 52 seats, that bloc could serve as a check on Trump if they choose to. However, if Republicans get up to 54 seats, bills could still pass even if all four of those senators defect (thanks to Vice President JD Vance's tie-breaking vote).
The size of Republicans' majority also makes a huge difference to the battle for Senate control in 2026. Democrats don't have a ton of pickup opportunities on the 2026 Senate map: Maine and North Carolina are probably the best ones, but Ohio, Texas and Iowa could be competitive as well. If Republicans stay at 52 seats, then Democrats have a plausible path to winning back the chamber by flipping the first two and maybe picking off one of the others too. But if Republicans get up to 54 seats, Democrats would have to win all five of those seats (and not lose any of their own). That's a tall order.