Grant County, Nebraska is one of the most pro-Trump places in America. In this rural community of about 700, the President won over 93 percent of the vote in the last election. But Grant County is also a place that has benefited hugely from the Affordable Care Act. In 2016, the law provided more than a quarter of its residents with tax credits to help them purchase health insurance.

Now, under the Republican plan to repeal and replace Obamacare, many Grant County residents would suffer steep cuts to the tax credits they've come to rely on. It's a nationwide pattern: Some of the harshest consequences of the GOP's health bill would fall on rural Republican strongholds — precisely the voters who helped elect Trump.

Among the counties where Trump won his biggest victories, nearly all would face deep cuts in tax credits under the Republican plan to replace Obamacare. And, in the parts of the country that would lose the most in tax credits, a majority of voters were Trump supporters.

The following chart shows the 25 counties where Trump captured the largest share of votes. In all but one, a typical middle-aged man buying health insurance on his own would lose money under the proposed GOP change, according to recent calculations from the Kaiser Family Foundation.

And, according to a Washington Post analysis of the Kaiser data, the counties whose residents stand to lose the most in tax credits under the new regime nearly all went for Trump in the last election. (This analysis excludes Alaska, where local voting data wasn't available.)

Why do Trump voters seem to suffer disproportionately from the change being pitched by the president and party they swept into office?

Unlike Obamacare, GOP's replacement plan  — dubbed the "American Health Care Act" — proposes tax credits that would not differentiate by where people lived, nor would it factor in local health insurance prices.

But health care costs vary wildly across the nation, and rural places, which largely went heavily for Trump, also tend to have some of the nation's highest health costs, in large part because they're areas with few doctors and scant competition among health care providers.

In Grant County for instance, the Kaiser Family Foundation estimates that under the new GOP plan, a 40-year-old man earning around $30,000 would lose $3,670 in tax credits — more than 10 percent of his income. A 60-year-old man with the same earnings would lose $12,950.

Now, take a look at the places with the highest support for Hillary Clinton in the last election. In these liberal enclaves, where Clinton won over 80 percent of the vote, many people would actually benefit from the new GOP plan. That’s because health care tends to be less expensive in urban areas, and the GOP’s tax credit would give residents in these low-cost areas more money.

In the suburbs of Atlanta, for instance, the same middle-aged man earning $30,000 would see his tax credit increase by about $1,620 under the AHCA, according to the Kaiser Family Foundation's calculations.

It is simply cheaper and easier to provide health care in places with a lot of people, said Gary Claxton, a vice president at the Kaiser Family Foundation. And because there tend to be more doctors and hospitals, insurers can play them off each other to bring down prices.

“In urban areas, it’s all about being able to negotiate efficient, lower-cost networks,” Claxton said. “That’s why there’s much more ability to get lower-cost premiums in those areas. In a rural area there’s not really much you can do by negotiating with the few existing providers that are there.”

Most people who have to purchase their own insurance qualify for Obamacare’s subsidies, which are tailored to each family’s situation. No matter how expensive health care is in your community, the law guarantees that you won’t have to spend more than a certain percentage of your income on your monthly premiums. In rural places, these sliding-scale subsidies can amount to well over $10,000 a year for older Americans, who face particularly high premiums, and they helped insulate people from the cost of rising premiums.

Under the Republican plan, the subsidies do scale with age — older people would get a few thousand dollars more than younger people. But in most cases this wouldn’t be enough to match Obamacare. In most of America, 60-year-olds earning under $50,000 a year would be better off under Obamacare’s more flexible system of subsidies, the Kaiser Family Foundation’s calculations show.

Who does benefit? In many cases, richer Americans. Obamacare currently limits its premium subsidies to those earning less than four times the poverty level — for an individual, that ceiling is around $50,000. The GOP plan would extend health care subsidies to people earning, in some cases, up to $100,000 a year. But richer Americans are more likely to already have health insurance through their employers, so they wouldn’t qualify for the tax credits, which only apply to people buying their own insurance on the private marketplace.

The Congressional Budget Office released estimates on March 23 for how House Republicans’ proposal to revise the Affordable Care Act might affect Americans. (Sarah Parnass, Bastien Inzaurralde/The Washington Post)