A majority of voters heading into the November 3 midterm elections say their minds are already made up about who they will support, but a sizable slice of the electorate could still shift the outcome in razor-thin races, including Iowa's Senate contest, according to a new Economist/YouGov survey.
The poll, conducted October 10-12, 2026, found that 78 percent of respondents with a Senate race in their state said their choice is locked in. Ten percent said they would consider voting for a different candidate, and another 7 percent remain undecided, Breitbart reported. With a margin of error of plus or minus 3.5 percent, that 17 percent of movable voters is more than enough to decide contests that are dead even.
Why Iowa's Senate Race Is Directly in the Path of These Numbers
The Cook Political Report currently lists seven Senate races as tossups between Republicans and Democrats: Alaska, Iowa, Kansas, Maine, Michigan, Ohio, and Texas. That means Iowa voters are among the roughly one in six Americans whose final decision could determine which party controls the Senate next year.
The numbers break down along party lines in a way that should grab the attention of every campaign office in Des Moines. Among independents, just 69 percent say their minds are made up on their Senate vote, compared with 89 percent of Democrats and 77 percent of Republicans. Among independents, 11 percent said they would consider a different candidate and 12 percent said they remain undecided.
In a state where independents have decided the last several statewide elections, those numbers are the whole ballgame. As NewsNation reported in its own poll with Decision Desk HQ this month, only about one-third of independents nationwide say they have made up their minds about how they will vote, and Democrats currently hold the edge among that group.
House Races Show the Same Pattern
The Economist/YouGov survey found nearly identical results for congressional races. Eighty percent of respondents said their mind is made up on their House vote, while 7 percent would consider another candidate and 8 percent remain undecided.
That combined 15 percent of persuadable or undecided voters looms over the 21 House races Cook rates as tossups, a list that includes six Democratic-held seats and 15 Republican-held seats. Another 21 races are rated as leaning toward one party or the other.
For Iowa's Republican incumbents, who have faced a barrage of outside spending this cycle, the question is whether that remaining pool of undecided voters breaks their way in the final weeks. Iowa Republicans have been hit with Iran war ads in recent months, part of a broader national effort to peel away moderate and independent voters.
Voters Expect Democrats to Win, But Expectations Are Not Results
The survey also asked respondents which party they expect to control Congress after the election. On the House, 43 percent said Democrats will hold the majority, compared with 30 percent who said Republicans will. On the Senate, 40 percent picked Democrats to take control and 35 percent said Republicans will keep it, while a quarter of respondents said they were not sure.
Expectations, however, have a poor track record of predicting outcomes, and Republicans are counting on an energized base and President Donald Trump's aggressive campaign schedule to close the gap. Trump has been holding rallies in key states including Ohio and Alaska this week, with additional stops planned in Georgia, Kentucky, Kansas, and North Carolina, according to Breitbart.
The Hill's election analysis this month noted that most voters make up their minds shortly after the primaries conclude, and the final fight is over the last 5 percent or so of true undecideds. That small group tends to be swayed by the overall political climate more than by any single ad or debate performance, the outlet reported.
What the Generic Ballot Means for the Final Stretch
National polling has generally shown Democrats with an advantage on the generic congressional ballot, and NBC News has noted that Democrats must win in multiple states Trump carried in 2024, some by double digits, to take back the House.
That map reality is why Iowa matters so much this cycle. A state Trump won comfortably is exactly the kind of territory Democrats need to flip to reach a majority, and it is exactly the kind of state where a few thousand undecided independents can make the difference between a Republican hold and a Democratic pickup.
The Economist/YouGov findings suggest most of the persuading is done. But with roughly three weeks between the poll's completion and Election Day, and with early voting already underway in Iowa, the campaigns that best turn out their locked-in supporters while winning over the last holdouts will control the Senate and possibly the House come January.
Gas prices, which have been a flashpoint all year, remain one of the few issues that could still move late deciders, and as one analysis noted, Iowa sits directly in the crosshairs of that dynamic.
Frequently Asked Questions
How many voters say their minds are made up for the 2026 midterms?
According to an Economist/YouGov survey conducted October 10-12, 2026, 78 percent of voters with a Senate race in their state and 80 percent of voters in House districts said their choice is already decided.
Which Senate races does Cook Political Report rate as tossups in 2026?
Cook lists seven Senate races as tossups: Alaska, Iowa, Kansas, Maine, Michigan, Ohio, and Texas.
When is the 2026 midterm election?
Election Day is November 3, 2026. Early voting is already underway in Iowa.