The Forecasting MachineOpen interactive report

Which party will win the 2026 US Senate election in Iowa?

The 2026 US Senate election in Iowa will be held on November 3, 2026. The nominees are Ashley Hinson (Republican) and Josh Turek (Democratic). Incumbent Senator Joni Ernst (Republican) is not running for re-election.

Forecasted on

Forecast probabilities

  • Democratic Party: 44.4%
  • Republican Party: 55.4%
  • Other Party / Independent: 0.3%

Reasoning

Ashley Hinson is the narrow favorite: the forecast assigns the Republican Party a 55.4% chance of winning, against 44.4% for the Democratic Party. An Other Party / Independent victory is assessed at 0.3%. The close polls and unusually unfavorable national climate for Republicans make a Turek win a substantial possibility, but they do not erase Iowa’s Republican lean or the risk that polls are again undercounting Republican support.

Democrats: A real opening, not a polling mirage

The strongest case for Josh Turek is that the race has become genuinely competitive in a national environment leaning strongly against Republicans. The final New York Times/Siena survey described Iowa as virtually tied, while some coverage characterized Democrats as leading in the state; Marist separately put Turek ahead 48% to 45% [e1480, e1481, e1477, e1271]. Those results fit a broader Democratic wave: recent national polls showed Democrats ahead on congressional preference, Trump’s approval was weak, and a late forecaster revision shifted nearly all of its changed ratings in Democrats’ favor [e1495, e1496, e1500, e1266, e1501, e1502, e1483].

There are local reasons the Democrat may outperform Iowa’s recent federal-election pattern. Turek has proved resilient in a Trump-carried state House district and has tried to blunt Republican cultural attacks with ads emphasizing his opposition to transgender women competing in women’s sports and to taxpayer-funded gender-affirming care [e1267, e1314]. The Des Moines Register endorsed him, and economic strains—including rising farm bankruptcies—give voters reasons to punish the party in power [e1487, e1281]. Trump’s last-minute rally in Iowa, amid changes to plans for his visit, underlines how consequential Republicans consider the state; it is evidence of attention and concern, though not proof of a late shift toward either candidate [e1503, e1490, e1476, e1478].

Republicans: The state’s habits still matter

The case for Ashley Hinson begins with the outside view. Iowa has voted increasingly Republican in recent presidential elections; Trump carried it by 13 points in 2024, Republicans hold a sizable voter-registration advantage, and no Democrat has won an Iowa Senate seat since 2008 [a3, a9, a12]. The closest recent Senate precedent is Joni Ernst’s 2020 race: even after polls suggested a tighter contest, she won by 6.5 points [a11, a12]. Hinson also entered the race with fundraising and outside-spending advantages, while the Republican-held seat is open rather than an incumbent’s to defend [a5, a6, e261].

The final polling picture deserves respect, but not blind faith. CNN analyst Harry Enten noted that Republicans have historically exceeded final Senate polling averages in states Trump previously won [e1497]. Iowa’s own 2020 experience makes that warning especially relevant. Early voting was down about 6% compared with the same point in 2022, and late-October Kalshi snapshots still favored Republicans in Iowa even as they favored Democrats in several other contested Senate races [e1279, e1322]. These are imperfect indicators, not verdicts, but they help explain why a tied poll does not translate automatically into a tied forecast.

Other Party / Independent: A formal option with little path

Libertarian Thomas Laehn is on the ballot, so a non-major-party outcome is possible in principle [e1493]. But the contest is framed around Hinson and Turek, and the available evidence offers no basis for expecting an independent or third-party candidate to win. That keeps the Other Party / Independent probability at 0.3%.

Why the forecast stays close

The evidence points in opposing directions, and neither side should be treated as decisive. Near-tied late polling, a poor national environment for Republicans, and Turek’s appeal pull the forecast toward Democrats; Iowa’s partisan baseline, its history of Republican-favoring polling error, and markets that continued to favor Hinson pull it the other way. The resulting 55.4% Republican probability gives Hinson a narrow edge while leaving a 44.4% chance for Turek—an unusually competitive prospect in a state that has recently leaned Republican.

Update summary

A new Times/Siena poll puts Iowa virtually even, reinforcing the close-race picture rather than materially changing it [e1480, e1481]. Trump’s final Iowa rally took place as scheduled, while a late round of forecaster revisions leaned broadly toward Democrats [e1476, e1483].

Cited evidence