Control of Congress will be decided by a handful of key Senate races as both parties battle for majority control in the closely divided chamber.

Democrats are targeting six Republican-held Senate seats in their effort to flip the chamber, while defending their current positions. With Republicans holding only a narrow three-seat majority, Democrats need to gain four seats to retake control.

The New York Times' interactive tracker identifies the most competitive races based on Cook Political Report ratings. CBS News has highlighted 10 key Senate contests that will likely determine which party controls the chamber in the 120th Congress.

Political analysts note that while the 2026 Senate map was initially seen as strongly favoring Republicans, recent polling trends have shifted the landscape. "Democrats are cautiously optimistic about flipping six Republican Senate seats," according to INAUF Daily reporting.

Before these races become questions of congressional power, several contests may first serve as litmus tests for party identity. Michigan's Senate race to replace a retiring senator has drawn five Democratic candidates, reflecting broader questions about the party's direction.

The outcome of these pivotal races will determine not only which party controls the Senate but also whether Republicans can maintain their governing trifecta under President Trump. All regular and special Senate elections scheduled for November 2026 will factor into the final balance of power.