Midterm elections in the United States have long served as a national referendum on the sitting president's performance. Voters often use these elections to express approval or disapproval of the administration's policies and direction, which can lead to significant shifts in control of Congress. Historically, the president's party tends to lose seats in the House of Representatives during midterms, with an average loss of around 25 seats. This pattern reflects the electorate's tendency to punish the party in power when the president's approval ratings are low.

The 2026 midterms are unfolding against this backdrop, with President Donald Trump's approval rating at historic lows. A Pew Research Center survey conducted from September 28 to October 4, 2026, found that only 30% of Americans approve of his job performance, the lowest of his second term. This is 8 percentage points lower than former President Joe Biden's approval at a comparable point in the 2022 midterm campaign. Such low approval ratings often translate into electoral losses for the president's party, as voters seek to check the administration's power.

The political environment is further complicated by the fact that many voters are motivated more by opposition to the president than by support for the opposing party. A recent analysis found that 63% of registered voters say Trump will be a factor in their vote for Congress, with more than twice as many saying their vote is against him rather than in support. This dynamic, where 'versus' is more powerful than 'for,' has become increasingly prominent in recent election cycles, shaping the strategies of both parties as they campaign for control of Congress.