With President Trump’s approval ratings languishing and Democratic candidates polling well, Rob Sand, Iowa’s state auditor, could become the state’s first Democratic governor in 16 years after November’s election.

Yet as governor, Mr. Sand would be unable to block Republican priorities if the G.O.P. wins a supermajority in the state legislature. Republicans would have the numbers to override any of his vetoes, as Govs. Laura Kelly of Kansas and Andy Beshear of Kentucky, both Democratic leaders in Republican states, know all too well.

So Democrats are leaning on a handful of moderate newcomers — bolstered by outside money — to flip several districts in November, and influence the balance of power in a state that has gone from consummate battleground to ruby red over the past decade.

Among them, Jill Alesch, a veteran and former prosecutor, is vying for an open State House seat in suburban Des Moines. Mike Tupper, a retired police chief and former Republican, is seeking to oust a first-term State House Republican in Marshalltown, a small blue-collar city.

“There’s a little bit of this sense of, ‘Rob Sand is this once-in-a-generation candidate, he’s going to win and suddenly he’s going to be able to wave a magic wand and transform the politics of Iowa,’” said Mandara Meyers, executive director of the left-leaning States Project, which spent more than $130 million nationally on state legislative races in the past two election cycles, and is now supporting Ms. Alesch and Mr. Tupper. “But you have no real teeth to your ability to actually improve the politics and improve lives in your state without that legislative power, too.”

Breaking a supermajority in states with divided government has become a priority in a highly polarized era. Democrats did it in North Carolina in 2024, giving Gov. Josh Stein, a Democrat, a backstop — on paper, anyway. In Vermont, Republicans ousted more than two dozen Democratic lawmakers, thanks to pocketbook issues, aiding Gov. Phil Scott, a moderate Republican.

Now the Democratic Legislative Campaign Committee wants to crack Republican supermajorities in states with competitive governor’s races, including Ohio and Kansas. The Republican State Leadership Committee, vowing to “withstand sustained pressure,” hopes to block a Democratic supermajority in Nevada that would weaken Gov. Joe Lombardo, should he win re-election.

Republicans downplay the Democrats’ aspirations in Iowa, a state that Mr. Trump won by 13 percentage points in 2024.

“We’ve seen this movie before,” said Pat Grassley, the Republican speaker of the Iowa House, and grandson of Senator Charles E. Grassley, also a Republican. “In 2020, out-of-state liberal donors poured millions into Iowa to try to buy the House, but Iowans saw right through it. In the elections since, Iowa has only trended more red.”

Democrats last held a trifecta in Iowa — both legislative chambers and the governor’s office — in 2010. Mr. Sand is now the party’s only statewide elected official, and Democratic legislators faced a Republican supermajority during the 2025 session. That made it easier for Gov. Kim Reynolds, a Republican who will retire this year, to cut unemployment taxes for businesses, approve a far-reaching private school voucher program and make Iowa the first to eliminate state civil rights protections for transgender people.

In August, however, Catelin Drey, a Democrat who campaigned on affordability, won a special election for a Sioux City State Senate district. That reduced the Republican margin to 33 to 17, or one shy of a supermajority, enabling Democrats to block some of the governor’s appointments.

Jeff Kaufmann, a former state representative who chairs the Iowa Republican Party, predicted Ms. Drey would lose in November. He was also “very bullish,” he said, that Republicans would regain a State Senate seat in eastern Iowa that delivered a 21-point margin for Mr. Trump in 2024, but narrowly elected a Democrat last year in a special election with low turnout.

Iowa House Republicans hold a 67-to-33 margin, the minimum for a supermajority.

In Polk County, home to many Des Moines bedroom communities, Ms. Alesch is competing against Nicole Hasso, a financial adviser. The district’s median household income is $110,000 — or $35,000 more than the state average — and affordability concerns linger.

Ms. Alesch, 48, a blunt-talking lawyer and retired lieutenant colonel, earned a Bronze Star after being deployed to Afghanistan. A gun-owning moderate who voted for John McCain, she has highlighted water quality concerns — mirroring Mr. Sand and his Republican opponent for governor, Zach Lahn — along with public education and food insecurity.

“I had to stop complaining and do something,” Ms. Alesch said while driving past Camp Dodge, the headquarters of the Iowa National Guard and her former stomping grounds.

Ms. Hasso, 55, a conservative Christian, has stressed the economy, property taxes and child care costs. She did not respond to calls and emails, but Mr. Kaufmann, the Republican chair, said her work ethic was unmatched, and her charm a major asset.

In Marshalltown, an hour northeast of Des Moines, Mr. Tupper, a former Marshalltown police chief, is challenging State Representative David Blom, a Republican. The area includes a large pork processing plant, and 50 languages are spoken in a school district with a sizable number of Mexican immigrants and refugees from Myanmar.

Mr. Tupper, 56, said he admired Robert Ray, a centrist Republican governor who welcomed Southeast Asian refugees in the 1970s. Mr. Tupper said he switched parties after Mr. Trump “pushed me over the edge” in 2016.

“The people that I’m talking to — they’re trying to figure out how they’re going to pay their rent and buy groceries,” he said. “They’re not paying attention to the Supreme Court or any other cultural issue that you might see debated on Fox News or CNN.”

Mr. Blom, a 28-year-old sheet metal worker and Marshalltown native, has pushed for low taxes and economic growth. He did not respond to calls and emails, but Mr. Kaufmann chalked up his upset win in 2024 over an entrenched Democrat to his earnest diligence.

“He just seems to be doing this for the right reasons,” Mr. Kaufmann said.