Midterm season is quickly approaching, and Democrats believe they are close to taking back control of the House of Representatives. Is midterm history doomed to repeat itself? Today, we are reviewing recent midterm elections and what the key factors were in each. The chart below shows elections in which there was a change of control in the House of Representatives (with the exception of the Republican win in 2024), with party ID, vote margins among independents, and number of House seats won by the winning party. Elections in red indicate a change in House control going to Republicans, blue to Democrats, and black where there was no change in control.
Party ID
In last November’s election, Republicans had a party ID advantage of +3 at the House level, propelling Republicans to a trifecta victory in the Senate, House and White House. This was structurally the same party ID advantage (+3) that was in place in 2022, the election which a Red Wave didn’t materialize.
1994 was a historic election in which Republicans won the House majority for the first time in 40 years, winning 230 seats. In that election, the party ID was tied. In 2010, party ID in the electorate was also tied, with Republicans winning 242 seats to gain the majority. Republicans had a much better party ID advantage in 2022 and 2024 than in 1994 and 2010. What gives?
Margins Among Independents
The margins among independents made the difference between a wave election and a close result. Winning independents by double digits in 1994 (+14) and 2010 (+19) produced wave elections. The same was true for Democrats in 2006 when they won independents by 18 and in 2018 with a margin of 12 among independents. In years that Republicans underperformed among independents (+2D in 2022; +1D in 2024), the result was much closer. In 2022, instead of the Red Wave that most Republicans were expecting, the House wasn’t called for Republicans until a week after Election Day.
Looking ahead to 2026, Republicans must improve performance with independents, or be able to sustain a +3 party ID in every election. Sustaining the GOP party ID advantage assumes Democrats do not increase as a percentage of the electorate (32% in 2024, having dropped from 37% in 2020) and that more Republican voters don’t become independents.
For Democrats, their party has declined as a percentage of the electorate, meaning that if they remain at this level, they will be more reliant on independents to win a majority. Their current political strategy of advocating for a government shutdown to show their base they are fighting against the President will not be helpful to that end.
For more, please see our post-election analyses.
