WASHINGTON — The personality looming over the 2018 midterms was President Donald Trump. The issue was health care, the top concern for voters as they decided how to cast their ballots.

This week’s election showed a nation increasingly — if belatedly — in step with former President Barack Obama’s approach to it.

Health care was the top issue for about one-fourth of voters, ahead of immigration and jobs and the economy, according to VoteCast, a nationwide survey of more than 115,000 voters and about 22,000 nonvoters conducted for The Associated Press by NORC at the University of Chicago.

Those most concerned with health care supported Democratic candidates overwhelmingly, helping the party claim the House.

While Republicans’ hold on the Senate grew, putting Democrats in control of the lower chamber makes it even less likely that Trump will be able to undo Obama’s overhaul, which created subsidized coverage for some lower-income people, allowed states to expand Medicaid coverage for others with the federal government picking up most of the cost, and barred insurers from discriminating against people with pre-existing medical conditions.

The law was one of Obama’s key legislative accomplishments, but it proved unpopular after Democrats passed it without a single Republican vote. A backlash propelled the GOP to take control of the House in 2010 and the Senate in 2014, significantly narrowing what Obama could accomplish.

But by last year, “Obamacare” was popular enough that a GOP-controlled Senate blocked an effort to scrap the overhaul.

That vote was a factor in the only Senate race where a Republican incumbent lost a re-election bid.

In Nevada, where the majority of voters said they disapproved of Trump’s handling of health care, Democratic challenger Jacky Rosen attacked incumbent Republican Sen. Dean Heller for supporting Trump’s effort to repeal the health care law.

“In time, changes will be made,” Mike Leavitt, health secretary under President George W. Bush, told the AP. “But repealing the statute is now not possible, even in the mind of the most ardent opponent.”

The health care impact of the election goes beyond Congress.

Voters in the Republican-dominated states of Idaho, Nebraska and Utah all passed ballot measures to expand Medicaid, which could bring coverage for an additional 363,000 low-income adults, adding to the 12 million already covered by the expansion elsewhere. Under the Affordable Care Act, federal taxpayers pick up most of the bill for the expansion. Starting in 2020, states will have to contribute 10 percent of the cost.

“For all the people who have been slipping through the cracks in our health care system in Utah, there is finally good news,” RyLee Curtis, campaign manager for Utah Decides Healthcare, said Wednesday on a conference call with reporters. “Help is on the way.”

Advocates, however, were disappointed by the outcome in Montana, where voters rejected a measure that would have made that state’s Medicaid expansion permanent with financing from a tobacco tax. The debate isn’t over, but it will move to the state legislature instead.

Jonathan Schleifer, executive director of The Fairness Project, which campaigned for the expansion measures, said states including Missouri, Florida and Oklahoma could be pursued for future ballot measures.

Democrats picked up governorships Tuesday in two states that may now expand Medicaid — Kansas and Wisconsin.

In Kansas, health care tied with immigration as voters’ top issue. In Wisconsin, which did not join the federal Medicaid expansion but does allow more adults into the program already, it was the biggest concern identified by about one-third of voters.

In both states, about 7 in 10 of voters who said health care was their main concern voted for the Democrat for governor.

That helped put Tony Evers over the top in his race against incumbent Republican Scott Walker in Wisconsin and pushed Laura Kelly to victory in a close race against Republican Kris Kobach in Kansas.

Kelly got big cheers in her victory speech when she called for a Medicaid expansion, which she said was important “so that more Kansans have access to affordable health care, our rural hospitals will stay open and the tax dollars we’ve been sending to Washington will come back home.”

Medicaid was also a key issue in Maine, where voters last year approved a ballot measure to expand but where the current governor, Republican Paul LePage, refused to implement it. Democrat Janet Mills campaigned on implementing it and defeated Republican Shawn Moody, who campaigned against expansion.

Tuesday’s election results were far less clear on where Americans stand on a move to universal health coverage, an idea that a growing number of Democratic candidates, including several considering presidential bids, have been backing.

In his campaign for governor in Florida, Democrat Andrew Gillum called health care for all a “north star” that the state should aspire to while offering up the intermediate step of expanding Medicaid as a must-do in the nation’s third most populous state. The majority of Florida voters in the AP survey disapproved of Trump’s handling of health care, and 3 in 5 also said it should be the government’s responsibility to provide coverage.

There, health care was tied with immigration as voters’ top concern and Republican Ron DeSantis, a former member of Congress closely aligned with Trump, won.

Meanwhile in Colorado, Jared Polis, a Democrat, was elected governor while promoting a single-payer health system for the state. Voters there rejected a ballot measure to create such a system two years ago.

Charles Idelson, a spokesman for National Nurses United, a group pushing for single-payer health coverage, said the number of supporters of the concept is increasing at all levels of government after the election despite what he called “vilification of that issue and the demagoguery of that issue” by Republicans in campaign ads.

Kathleen Sebelius, health secretary under Obama, told the AP she expects House Democrats to start designing a framework for covering all Americans and for that to be a major issue in 2020 elections.

“One of the things this election clearly demonstrates is that health care for all is a unifying principle for the Democrats,” she said. “We have been working toward that goal since 1965, when Medicare and Medicaid were passed.”

___

Mulvihill reported from Philadelphia.