Republicans face a serious challenge to their 53-47 Senate majority in the November 2026 midterm elections after Cook Political Report and Decision Desk HQ rated Texas and Iowa toss-ups. Five of Cook’s six toss-up Senate seats are held by Republicans, and only one is in a state President Donald Trump lost in 2024. Democrats must retain their seats and flip at least four others to control the chamber. James Talarico is polling nearly level with Texas Attorney General Ken Paxton, while former Paralympian Josh Turek is challenging Rep. Ashley Hinson in Iowa. Cook rates Senate control as a toss-up but gives Republicans a slight advantage, while DDHQ puts the GOP’s chance of retaining the chamber at 54% and Democrats’ at 46%, narrowing a 20-point Republican advantage from the previous month. Trump’s approval is 38% in Nate Silver’s Silver Bulletin polling average, and Democrats lead the House generic congressional ballot despite Republicans’ 218-213 House majority. A Democratic takeover of either chamber, or a split Congress, could constrain Trump’s agenda and enable investigations into whether he used the presidency for personal enrichment.