A Trump administration plan that would severely penalize immigrants for accessing public benefits has only just been published, but advocates say that legal U.S. residents had already been cutting themselves off from critical services—making the seemingly impossible choice between their well-being and a green card.

On Saturday, the Department of Homeland Security put forward a 447-page proposal that would make it extremely difficult for immigrants to come to the United States if they are deemed likely to use public assistance programs like food stamps, housing vouchers, prescription drug subsidies, and Medicaid. The policy would also weigh heavily against current U.S. residents who wish to obtain a green card, entitling them to permanent residence in the United States.

Advocates say that the proposal has already produced a chilling effect on the use of benefits to which immigrants and their citizen relatives are legally entitled—something Homeland Security acknowledged is an inevitable consequence of the policy.

“It’s not a surprise that this is causing further panic among immigrant communities,” Tanya Broder, a senior staff attorney with the National Immigration Law Center, told The Daily Beast. “These are very uncertain times, and that fear has a real public health and economic effect on all of us. We expect that many will avoid going in to get the services that they need—and for which their children are eligible—because of this fear and uncertainty.”

Potential immigrants and permanent residents have long been evaluated on their likelihood of becoming dependent on the government, a status known as being a “public charge.” Currently, a person is not considered a potential public charge unless they are demonstrated to require substantial cash assistance or institutionalization for long-term medical care. Under those criteria, a person may be deemed inadmissible to enter the United States and ineligible for a green card.

But under Homeland Security’s new framework, those criteria would be replaced by an elaborate weighted system that greatly expands the definition of a public charge. Use of monetized benefits like food stamps, Social Security and WIC, a federal assistance program that provides healthcare and nutrition to low-income pregnant women, would be counted negatively against potential permanent residents. So, too, would use of “non-monetized” benefits like public housing subsidies, and Medicaid. Other factors that could count as negatives for a green-card applicant include age, insurance status, English proficiency, and even credit score.

Homeland Security Secretary Kirstjen Nielsen said in a statement on Saturday that the policy would “promote immigrant self-sufficiency and protect finite resources by ensuring that they are not likely to become burdens on American taxpayers.”

But advocates warn that immigrants with legal status are now terrified to access programs that they need—and to which, as taxpaying legal U.S. residents, they are legally entitled.

Kate Chaltain, an immigration attorney based in New York City, told The Daily Beast that multiple clients have already contacted her since the proposed rule was published, each concerned that the policy might affect their ability to change their legal status in the future.

“I have one client who was planning to apply for citizenship—she’s a green card holder now—but may not now because she received Medicaid assistance when she had breast cancer a few years ago,” Chaltain said. “I have another client who is concerned because she received WIC when she was pregnant with her U.S. citizen son.”

Forced to decide between immigration benefits and government subsidies that their taxes pay for, Chaltain said that many of her clients will choose to forego crucial public assistance rather than jeopardize their pathway to permanent residency or citizenship.

“We will see fewer people applying for immigration benefits they would have previously been eligible for because of this,” Chaltain said, an outcome that “directly harms U.S. citizen children and immigrant children, which has become a hallmark of this administration’s policies.”

That decision could also have dire public health consequences for both immigrants and native-born American citizens.

The government’s own proposal found that among the consequences of the rule change include “worse health outcomes” for immigrants and their citizen relatives, since the policy would inevitably disincentivize otherwise eligible sick people from seeking medical care. The Department of Homeland Security stated that this could lead to “increased prevalence of obesity and malnutrition, especially for pregnant or breastfeeding women, infants, or children.”

In the proposal, the Department of Homeland Security also estimated that more than 324,000 people would disenroll from benefits “due to concern about the consequences to that person receiving public benefits and being found to be likely to become a public charge,” even if they are eligible for them.

That squares with what the National Immigration Law Center has seen among its clients, Broder said.

“We saw a spike in people afraid to continue medical treatment, and to get the healthcare and nutrition that they need to stay strong, thrive, and grow and contribute to our communities.”

Earlier this month, Politico reported that immigrants have already begun dropping out of a federal nutrition program for their babies out of fear the Trump administration will use their acceptance of federal aid against them. Enrollment in WIC has reportedly dropped by as much as 20 percent in at least 18 states, which could have major repercussions on the American-born children of legal immigrant residents.

“The federal agencies have received proof that pregnant women were avoiding prenatal care—their pregnancies became more complicated,” Broder said. “Children are being born with medical problems that could have been avoided had their moms received proper prenatal care.”

Avoidance of vaccines, Broder added, poses a public health threat as well.

“There’s no way to isolate immigrants from citizens,” said Broder. “We live together in families, in communities, and anything that is supposedly targeting one group is going to affect all of us.”

The plan, the latest in a long rollout of Trump administration policies and proposals that would have a deleterious effect on both legal and undocumented immigrants, runs counter to the frequent Republican claim that the party supports legal immigration. The rule change would specifically target legal immigrants and their U.S. citizen children, and have little bearing on undocumented immigrants.

Despite that, Chaltain said that it is extremely likely that immigrants who are undocumented but potentially eligible for benefits for themselves and their children will forego those benefitrs “out of fear of losing the ability to get legal status in the future.”

For legal residents, the fear that an even more draconian policy might lurk around the corner is just as palpable, and enough of a reason to avoid being seen as “taking advantage” of public benefits.

“The rule is not as broad as the fear,” Broder said, noting that children are still, on paper, eligible for the Children’s Health Insurance Program and for school lunch assistance. “The much broader and more significant problem will be caused by people broadly avoiding critical services.”

“School lunch is not named, so that likely won’t be weighed [against those seeking a green card], but that won’t be fully understood,” Broder explained. “Immigrant parents could still get health coverage for their child…. but the likelihood that they’ll avoid those benefits is great.”