The Democratic Party led the generic congressional ballot by 7.6 points at the end of May, according to RealClearPolitics. Since the start of the second Trump Administration, the highest Democratic lead recorded by RCP was on May 28, 2026, when Democrats led Republicans 49% to 41%, an eight-point margin.

This is the second-highest lead either party has had heading into May of a midterm year since 2006. The highest recorded average was in May 2006, when, according to RealClearPolitics, Democrats had a 9.8-point lead. Since 2002, Republicans have only led at the end of May just once, in 2022, when they had a 1.9-point lead on the generic Congressional ballot.

Across all election cycles, comparing the polling average at the end of May to the final results, the cycle closest to the final result was 2022, when Republicans won by 2.8%, a disparity of just 0.9%. The cycle with the biggest disparity between polling and election results was 2010, when Democrats led the generic ballot by 0.4%, but Republicans ultimately won by 6.8%, a 7.2% gap.

For the 2026 cycle, Democrats first took the lead in the RCP average on March 3, 2025. In 2022, Republicans first took the lead on November 13, 2021. In 2014, Republicans took the lead on November 21, 2013, and went on to win that cycle, and in 2010, Republicans took the lead on December 14, 2009. Comprehensive data were not available for 2002 or 2006. 2018 was the only cycle in which one party led from start to finish, with Democrats having a lead in early RCP averages and ultimately winning the Congressional vote.

To read more about Ballotpedia’s polling coverage, click here.