As Americans head to the polls for the final day of midterm voting on Tuesday, candidates are making their final appeals to voters in high-stakes House and Senate races that will determine the balance of power in Congress, where Republicans currently control both chambers.

A shift in the balance of power could curb the executive influence of President Donald Trump and could have meaningful implications on domestic and foreign policy amid a generally unpopular U.S. war with Iran, climbing inflation and record high fuel prices that have strained American households.

Here's a look at some key Senate, House and gubernatorial races to watch that could help define the outcome of the 2026 midterms: Thirty-five Senate seats are in play during the 2026 midterms, but the outcome of a few competitive races in both battleground and traditionally Republican states, will determine which party will control the upper chamber of Congress next year.