They spoke anxiously about rising premiums, deductibles, copays and drug costs. They were especially upset by surprise bills for services they believed were covered. They said their coverage was hopelessly complex. Those with marketplace insurance — for which they were eligible for subsidies — saw Medicaid as a much better deal than their insurance and were resentful that people with incomes lower than theirs could get it. They expressed animosity for drug and insurance companies, and sounded as much like Bernie Sanders supporters as Trump voters. One man in Pennsylvania with Type 1 diabetes reported making frequent trips to Eastern Europe to purchase insulin at one-tenth the cost he paid here.

Surveys show that most enrollees in the Affordable Care Act marketplaces are happy with their plans. The Trump voters in our focus groups were representative of people who had not fared as well. Several described their frustration with being forced to change plans annually to keep premiums down, losing their doctors in the process. But asked about policies found in several Republican plans to replace the Affordable Care Act — including a tax credit to help defray the cost of premiums, a tax-preferred savings account and a large deductible typical of catastrophic coverage — several of these Trump voters recoiled, calling such proposals “not insurance at all.” One of those plans has been proposed by Representative Tom Price, Mr. Trump’s nominee to be secretary of Health and Human Services. These voters said they did not understand health savings accounts and displayed skepticism about the concept.

When told Mr. Trump might embrace a plan that included these elements, and particularly very high deductibles, they expressed disbelief. They were also worried about what they called “chaos” if there was a gap between repealing and replacing Obamacare. But most did not think that, as one participant put it, “a smart businessman like Trump would let that happen.” Some were uninsured before the Affordable Care Act and said they did not want to be uninsured again. Generally, the Trump voters on Medicaid were much more satisfied with their coverage.

There was one thing many said they liked about the pre-Affordable Care Act insurance market: their ability to buy lower-cost plans that fit their needs, even if it meant that less healthy people had to pay more. They were unmoved by the principle of risk-sharing, and trusted that Mr. Trump would find a way to protect people with pre-existing medical conditions without a mandate, which most viewed as “un-American.”

If these Trump voters could write a health plan, it would, many said, focus on keeping their out-of-pocket costs low, control drug prices and improve access to cheaper drugs. It would also address consumer issues many had complained about loudly, including eliminating surprise medical bills for out-of-network care, assuring the adequacy of provider networks and making their insurance much more understandable.