Republicans currently hold a 53-47 Senate majority ahead of the November 2026 midterms, where 35 seats are contested and Democrats are projected to gain ground in multiple toss-up and lean races including Ohio, Maine, Alaska, and Iowa. Forecasts from multiple models assign Democrats roughly a 65% probability of securing control. The June 2026 US-Iran memorandum of understanding, which reopened the Strait of Hormuz, lifted certain sanctions, and initiated a 60-day negotiation window on broader issues, has divided Republican senators, with defense hawks criticizing the terms on sanctions relief and deferred nuclear questions while others viewed it as necessary to stabilize energy markets. Ongoing implementation challenges and the prior conflict's impact on fuel prices remain factors influencing voter assessments in competitive states.