12 key races that will determine who controls the Senate

Updated on: September 9, 2026 / 9:43 AM EDT / CBS News

Washington — The key contests that will determine who wins control of the Senate are now set for the fall midterm elections, as the 2026 primary season wraps up.

Republicans are fighting to hold onto their majority, where the GOP currently controls 53 seats. The map this cycle initially appeared to be working in their favor, since most of the 22 seats the GOP is defending are in states that President Trump won by comfortable margins in 2024. But the unpopular war with Iran and persistent affordability issues have helped make several Republican-held seats increasingly competitive, while Democrats are trying to defend a handful of other seats from possible GOP flips.

To secure a majority, Democrats would need to net four seats in November's election.

These are the 12 key Senate races to watch:

The Maine Senate race was closely watched even before personal controversies arose around the Democratic nominee, oyster farmer Graham Platner. In July, he bowed out of the race in the wake of a sexual assault allegation.

Maine Democrats then rallied around Troy Jackson as their nominee to take on GOP Sen. Susan Collins in…

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