MONTGOMERY, W. Va. — Communities like this aging West Virginia coal town along the Kanawha River were key to President Donald Trump’s victory last year; more than two-thirds of voters in surrounding Fayette County backed the Republican nominee.

Now, families in this rural county and hundreds like it that supported Trump face the loss of a critical safety net for children as congressional Republicans move to cut hundreds of billions of dollars over the next decade from Medicaid, the half-century-old government health plan for the poor.

Much of the debate over GOP efforts to roll back the Affordable Care Act has focused on the impact cuts would have on working-age adults, millions of whom gained coverage under the health care law that President Barack Obama signed in 2010.

But in Fayette County and 779 other mostly rural counties across the country — the vast majority of which went for Trump — more than half the children rely for coverage on Medicaid and the related Children’s Health Insurance Program, or CHIP, according to a Los Angeles Times analysis of county voting data, census data and Medicaid enrollment data.

That is stoking alarm among parents, pediatricians and other medical providers in West Virginia and other rural states, including Arkansas, Tennessee, New Mexico and Maine.

“There is just no way to cut Medicaid on the scale that they are talking about and avoid hitting kids,” said Dr. Traci Acklin, who grew up in Fayette County and now runs the only pediatrician’s practice in Montgomery out of the first floor of a community hospital founded a century ago to care for sick miners.

“Without the health insurance, kids aren’t going to get the immunizations and the check-ups. There are going to be more lost days of school. More trips to the emergency room. … It would be food or health care for a lot of these families.”

These concerns are, in turn, putting increasing pressure on Republican lawmakers, such as West Virginia Sen. Shelly Moore Capito, one of several GOP senators whose reservations about Medicaid cuts stalled the GOP health care bill in the Senate last week.

Over the last two decades, successive presidents, congressional leaders and state governors from both parties have steadily expanded health coverage for children through Medicaid and CHIP, which was created in the late ’90s to provide coverage for the children of working-class families who earned too much to qualify for Medicaid.

Today, just 5 percent of kids nationwide lack health coverage, down from nearly 14 percent two decades ago. That’s a gain which many experts see as one of the great public health successes of recent decades.

A growing body of research shows Medicaid leads to better health, improves children’s reading and test scores, lowers high school drop-out rates and even increases future earnings.

“There is very strong return on the Medicaid investment,” said Joan Alker, executive director of the Center for Children and Families.

But the House and Senate Republican health care bills — which go well beyond repealing Obamacare, as the Affordable Care Act is often called — threaten changes that could reverse many of those gains.

Overall, the Senate GOP legislation would slash more than a third of federal Medicaid funds over the next 20 years and nearly double the ranks of the uninsured by 2026, according to recent analyses by the nonpartisan Congressional Budget Office.

Budget analysts and many state governors, including some Republicans, predict such a retrenchment will have a devastating impact, including on children, as some 45 million low-income children rely on Medicaid and CHIP nationally.

“We as a country should stop and realize the number of children whose lives are at stake here,” said Marcy Doderer, chief executive of Arkansas Children’s Hospital.

This wasn’t the vision Trump promised on the campaign trail. He pledged repeatedly to ensure all Americans were taken care of.

More recently, the president called for a health care bill “with heart.”

Many GOP officials insist they won’t jeopardize coverage gains, pledging their health care legislation will ensure “that nobody falls through the cracks.”

But in small towns and rural areas with few other resources, Medicaid and CHIP are among the only things that keep many families from falling into those cracks.

“I don’t know what we would have done without it,” said Nikki Given, a young mother who brought her 1-year-old son, Connor, to Acklin’s office recently to have his ears checked. Medicaid coverage has allowed Connor to get the intravenous antibiotics and minor surgery he needs to relieve persistent ear infections.

Given works at a daycare that doesn’t have a health plan. Her fiance, who is about to start work at local sawmill, also won’t get health benefits.

Without the Medicaid coverage, Connor’s antibiotics and medical care would have cost the parents several thousand dollars, Acklin estimates.

Medicaid and CHIP provide a critical backstop across this region of West Virginia, where coal mining jobs have increasingly been replaced by lower-paying work that often doesn’t provide health insurance.

Acklin, who came back to Montgomery to practice 16 years ago, sees many families who struggle to put food on the table. Routine checkups regularly uncover heart murmurs, untreated asthma and other serious medical issues.

And with the advent of the opioid epidemic, Acklin is seeing more children being raised by grandparents.

Some of the same issues challenge large urban areas. Several of the 780 counties most dependent on Medicaid and CHIP to cover children are large cities with more than 1 million residents, including Miami, Philadelphia and parts of New York City, which covers five counties.

But in many big cities such as Los Angeles and Chicago, where jobs are relatively plentiful, most children don’t have government health coverage, according to the enrollment data, which was assembled by the Center for Children and Families at Georgetown University.

By contrast, 622 of the 780 counties where a majority of children are on Medicaid and CHIP have populations of less than 50,000. Most of the counties are overwhelmingly white, with the exception of predominantly African-American counties in the Mississippi Delta and heavily Latino counties in New Mexico and along the Rio Grande Valley in Texas.

noam.levey@latimes.com