2026 Midterms: Congress Balance of Power? — For Feb 2027

This market asks which party will control the House and Senate after the 2026 midterms, with outcomes covering every combination of chamber control plus full sweeps for either party. Across Polymarket, Kalshi, and Polymarket US, a full Democratic sweep is the clear favorite at a 64.0% consensus probability, followed closely by the narrower "D-House, D-Senate" outcome at 63.5%. The two Republican-favorable splits — D-House/R-Senate and R-Senate/D-House — sit nearly tied in the high-20s (28.5% and 27.5%), while a full Republican sweep trails at just 8.5%. Pricing is tightly aligned across venues, with spreads generally under one point, though the Republicans Sweep outcome shows a modest 2.0-point gap between Polymarket (7.5%) and Polymarket US (9.5%). The dominance of the Democratic Sweep outcome reflects broader forecasting consensus heading into the midterms. Independent models echo this lean: Decision Desk HQ's 2026 midterm forecast gives Democrats a 75% chance of winning the House and a 56% chance of winning the Senate as of early October 2026, while analysts at Silver Bulletin note Democrats are in an excellent position to retake the House and are also favored to retake the Senate. Polymarket's own market commentary points to national generic ballot surveys showing Democrats ahead by roughly 8 to 12 points among likely voters, aligning with historical midterm penalties for a president near 38-39 percent approval, and highlights Senate forecasts shifting toward Democrats being competitive or ahead in seats including Texas, Ohio, Kansas, Maine, Michigan, and Nebraska. Overall, the cross-platform data points to strong, consistent confidence in a Democratic sweep of Congress, with only minor pricing discrepancies suggesting traders broadly agree on the current political trajectory.