Midterms: How high does the Democratic wave crest?

Voters heading to the polls on November 3 face a House race defined by heavy advertising and redrawn maps rather than a simple partisan sweep. Ad spending data from the final week of the campaign suggests the central question is no longer whether Democrats will take control, but by how much. The core battle involves determining the height of a potential Democratic wave in a midterm environment that traditionally favors challengers.

An NPR analysis identifies 70 districts where both parties have committed at least six figures to final messaging efforts. This expansive competitive landscape includes seven-figure ad buys in deep-red communities in Tennessee, Oklahoma, and Arkansas. Resources are also pouring into districts where Republican gerrymandering might backfire. In toss-up districts in Michigan, North Carolina, New York, and Florida, each side has invested more than $10 million. The most expensive races, such as Michigan's 7th and North Carolina's 1st, have seen over $12 million in planned spending each.

The shift in momentum is evident in how candidates are managing their campaigns. In ten districts that voted for one party's presidential candidate and the other's House nominee in 2024, Republicans have slashed ad reservations in recent weeks, according to AdImpact data. These seats include districts held by Democratic Reps. Adam Gray, Nellie Pou, and Marie Gluesenkamp-Perez, as well as the seat of retiring Republican Rep. Don Bacon. The latest NPR/PBS News/Marist poll shows Democrats holding a 10-point advantage among registered voters and 8 points with likely voters on the generic congressional ballot.

Economic factors are driving voter sentiment, with cost of living remaining the top concern. Rising gas prices, tariffs, and the ongoing war in Iran are weighing on household budgets. A record number of congressional retirement announcements has also amplified an anti-incumbency streak in primary elections. These dynamics are creating a broader pool of competitive seats before accounting for candidate quality or outside spending.

Redistricting after a Supreme Court decision that rolled back part of the Voting Rights Act has scrambled the electoral map. Republicans shifted boundary lines to add conservative voters into districts held by Democratic Reps. Marcy Kaptur, Don Davis, Shomari Figures, and Darren Soto. Democrats made similar moves in California for districts held by Republican Reps. James Gallagher, David Valadao, Ken Calvert, Darrell Issa, and independent Kevin Kiley. Only Figures and Soto are in districts currently rated as favoring Republicans.

The 70 races with substantial ad spending from both parties voted for President Trump by an average of nine points in 2024. Sixty districts are listed as priorities by both the Democratic and Republican House campaign arms, reflecting the impact of the Trump administration's unpopularity. However, not every race will end close. Many of the Democratic Congressional Campaign Committee's designated districts in play gave Trump closer to 60% of the vote in 2024 and have seen little ad spending from either side.

Cook Political Report ratings list Democrats as favored in 220 seats. They have 17 seats listed as toss-ups and another 30 that are potentially competitive but lean toward the GOP. Republicans currently hold a narrow 218-214 seat advantage, a lead that appears likely to give way to Democratic control given the current polling and spending patterns. Millions of voters have already cast their ballots, with final results pending as the campaign winds down.