The Trump administration is reportedly preparing to propose a rule that would deter legal immigrants from using government services. The rule, according to leaked drafts of it, would make it harder for legal immigrants to become citizens or get green cards if they have ever used a wide range of public welfare, including Medicaid, food stamps, the Children’s Health Insurance Program (CHIP) and subsidies to buy health insurance.

There are already scattered reports of immigrants, afraid of jeopardizing their shot at permanent residency, choosing not to use health benefits for which they -- or their children -- qualify. If a significant number of legal immigrants forgo health insurance, that could have negative ripple effects on so-called Obamacare premiums and on the health-care system as a whole.

"If there’s a real reduction in enrollment, then in those geographic areas with a higher immigrant population, it could really impact the marketplace," says Dania Palanker, associate research professor of health policy at Georgetown University.

The marketplace has struggled to attract younger, healthier populations, which has contributed to rising premiums. If more legal immigrants go uninsured, they could exacerbate that issue.

"We do know that Hispanic people tend to use less medical care, so to the extend that we’re pulling heathlier people out of the pool -- or at least people who are less likely to use a lot of care -- it hurts the market that remains. But how much of an impact it will have on premiums is hard to say because we just don’t have the data," says Linda Blumberg, a health policy fellow at the Urban Insititute.

People are asked about their immigration status when they enroll in health plans, but those numbers are not made public. According to a report released this month by the New England Journal of Medicine, 19 percent of non-citizen adults use Medicaid, and 38 percent of their children are either on Medicaid or CHIP. If those populations are discouraged from enrolling, the study estimates that up to 1 million people would suddenly become uninsured.

"If there’s more uninsured people, that not only effects them, but it impacts the financing of medical care," says Blumberg. "If things get desperate and you show up at an emergency room, that puts pressure on providers with increases in uncompensated care -- and that in turn puts pressure on state and local government budgets."

Health care is already one of the government's biggest spending areas, reaching more than $4 trillion in 2016, averaging out to $10,348 per person, according to the Centers for Medicare and Medicaid Services.

While it's unlikely that the rule would be finalized in time for this fall’s open enrollment period, experts say that the Trump administration’s harsh immigration policies are already having an impact on health care in communities across the country.

Marielena Hincapié, executive director of the National Immigration Law Center, says she’s been hearing anecdotal evidence of immigrants -- even those with cancer -- dropping their insurance for fear of getting deported. The Center for Law and Social Policy conducted a report last year, finding that since President Trump took the White House, there has been an uptick in missed doctor's appointments among immigrants. 

"Our biggest concern is that kids are going to go hungry and they’re going to be losing access to basic health care," Wendy Cervantes, a senior policy analyst at the Center for Law and Social Policy, told Governing when news of the rule was leaked earlier this year.

The Trump administration is expected to release the rule this month or next, opening it up to a public comment period that would likely be met with resistance from immigration, health care and social services advocates. Even if the rule isn't enacted, experts say it has instilled fear in many communities -- and that could be enough to rattle the health-care system.

"The direct effect will depend on how large of a population that’s impacted," says Blumberg. "But the chilling effects could make those impacts even larger."

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