US midterm elections 2026: A new Congress could change Trump's legislative agenda; what house control means for Washington

US midterm elections 2026: The 2026 US midterm elections will shape US president Donald Trump’s remaining tenure and the 2028 presidential cycle, with Democrats projected to take the House of Representatives, while the Senate is a closer call.

A separate forecast from Cornell political scientists gives Democrats an 8-in-10 chance of securing a majority in the House. The forecast anticipates Democrats winning approximately 226 seats to Republicans’ 209, although simulations show as few as 206 Democratic seats or as many as 258 are statistical possibilities.

US Midterm Elections 2026 House Forecast

Cornell’s forecast was released on September 3 and is based on data collected at least 100 days before the November 3 election. The researchers presented the forecast at the American Political Science Association’s annual meeting.


Cornell political scientist Peter K. Enns said the forecasts are not deterministic and that there is uncertainty.

The Cornell model predicts outcomes for all 435 congressional districts and was updated to reflect recent redistricting. It considers factors including how a district voted previously, expert assessments of the likely winner, whether an election is competitive or unopposed, campaign donations, incumbent status and polling data.

Through 2024, the model achieved an overall accuracy rate of 96%, including correctly forecasting two-thirds of races that experts considered 50-50 “toss-ups,” according to Cornell.

What House Control Could Mean for Trump

Chatham House says a Democratic majority in either or both congressional chambers could allow Democrats to block Republican legislative moves. However, it says this would not automatically result in durable guardrails or clear policy shifts.

Even with control of both chambers, Democrats would struggle to drive policy through legislation because presidential vetoes and the lack of the required supermajorities could prevent them from overcoming presidential opposition, according to Chatham House.

Chatham House says the White House could respond by relying more heavily on executive authority, including executive orders, emergency declarations and regulatory actions.

Government Funding and the Debt Ceiling

Chatham House identifies fiscal matters as an area where Democrats could have leverage, even if they take only the House.

President Trump needs congressional action to fund the government and raise the debt ceiling, according to Chatham House. Congress raised the debt ceiling by $5 trillion in 2025, and the limit is expected to be reached by mid-2027. Extraordinary measures could then provide an additional six to nine months.

Trump is pushing Republicans to use the budget reconciliation process to lift the debt limit by another $5 trillion. Chatham House says reconciliation requires a budget resolution adopted by both chambers, meaning a Democratic House alone would rule out that route.

Unlike the debt limit, reconciliation cannot be used for regular appropriations. Chatham House says Republicans will need Democratic support to find a solution before federal funding expires on December 11.

Why Senate Control Matters

Chatham House says withholding approval for presidential appointments could provide leverage, particularly in the event of a Supreme Court or Federal Reserve vacancy.

However, this would work only if Democrats retake the Senate, which confirms presidential nominees.

Congressional Investigations and Impeachment

A change of control in Congress could also lead to widespread investigations, according to Chatham House. Areas mentioned by the think tank include Trump family business dealings and the Iran war.

Congress has powers including the ability to subpoena testimony and documents, although Chatham House says these powers can face enforcement challenges.

Presidential impeachment is another potential issue that could resurface. Chatham House says impeachment proceedings can be costly and time-consuming but may fail to deliver concrete results.

US Midterm Elections 2026 and Trump’s Remaining Tenure

Cornell’s forecast gives Democrats an 8-in-10 chance of securing a House majority and anticipates approximately 226 Democratic seats compared with 209 Republican seats. Cornell also emphasizes that the forecast is not deterministic and that uncertainty remains.

Chatham House says Democrats are projected to take the House while the Senate is a closer call. It also says the midterm results will shape Trump’s remaining tenure and the 2028 presidential cycle.