The obstacles to gaining citizenship in this country grow higher by the day. Some of these new hurdles are dramatic: The administration has placed severe restrictions on asylum seekers, and the military has been deployed to string concertina wire at the U.S.-Mexico border. Other changes are dry and bureaucratic, but no less potentially devastating. One especially consequential policy shift is the Trump administration’s proposal to modify the “public charge” rule — which it can do without consulting Congress.

The rule was designed to bar people from permanent residency who would be dependent on public support for most of their income. Gaining legal permanent residency (a “green card”) is a critical step before most immigrants can apply for citizenship, and the public-charge rule, whose origins as a federal policy date to 1882, has long been a tool to screen out “undesirable” immigrants from eventually becoming citizens.

Currently, to evaluate whether someone is likely to become a public charge, the government looks at whether an applicant for a green card has used cash-based benefits such as Temporary Assistance for Needy Families (TANF) to support themselves, and at what level, and the Department of Homeland Security can deny a green card application based on the answers. The Trump administration wants to add many more factors to the public-charge determination, including whether the applicants get SNAP (food stamps), Medicaid and Section 8 housing vouchers.

Very few noncitizens without green cards qualify for public benefits, but the new public-charge proposal adds additional socioeconomic factors that can contribute to a ruling against permanent residency, including low income, large family size and old age. Applicants with certain preexisting health conditions also could be rejected. Under the new rules, people whom the government suspects of being at risk of becoming a public charge may be granted legal permanent residency but could be asked to post a $10,000 bond, which they would lose if they went on government aid.

The Kaiser Family Foundation estimates that nearly 94 percent of noncitizens currently in the country have at least one factor that could weigh against them if they were to apply for public residency under these rules, and over 40 percent have a “heavily weighted factor” that could hurt their chances. This proposed rule change buttresses the false narrative that immigrants are a negative burden on the country, unfairly draining taxpayer resources, despite countless studies that show immigration as a positive contributor to the country’s economy.

But advocates for immigrants are also worried about a predictable side effect of this rule: Noncitizen parents will not seek health insurance for their citizen children, even though they are entitled to do so — and coverage rates for those children will drop, possibly dramatically. Since the Affordable Care Act was passed, the United States has made tremendous strides in insuring children who are citizens but have noncitizen parents. (It’s a very large group: Roughly one in four children in the country falls into that category.) In 2008, 84 percent had health insurance. By 2016, that figure had risen to 94 percent. All those gains could easily be erased.

This month, Urban Institute researchers estimated that nearly 6.8 million U.S. children who have at least one noncitizen parent are enrolled in Medicaid and CHIP, and they said that group is at high risk of losing their coverage.

Additionally, the Kaiser Family Foundation report concluded that the proposed change could lead to Medicaid and CHIP enrollment among citizen children with noncitizen parents dropping by somewhere between 15 percent and 35 percent. The low end of that range would mean 875,000 kids losing coverage under those programs; the higher estimate would mean 2 million losing coverage.

To be clear, the government would not be directly repealing coverage from these children. Instead, the loss would stem from the “chilling effect” of causing parents to fear that they will be judged as asking for too much from the government, thereby endangering their own citizenship chances. In truth, the new public-charge rule does not actually count the children’s use of Medicaid or CHIP as a negative factor for their parents’ green card applications, but that nuance gets missed in immigrant communities. Widespread fear is already causing families to take their children off the rolls of vital programs

We’ve seen that fear firsthand. At our health center, La Clinica del Pueblo, we have served a primarily immigrant patient population in the D.C. metro area for 35 years, regardless of ability to pay. We have already seen our patients react to this proposed rule by making unfortunate and harmful choices. One young mother dropped out of the WIC program, deciding to forgo support for the nutritious foods that would ensure her toddler’s healthy growth and development. Another patient, the possessor of a green card for 10 years, gave up food stamps — and is going hungry — because she heard a rumor that any immigrants who get benefits could get deported.

Our insurance enrollment specialists, hard at work to sign up folks for insurance through the Affordable Care Act exchanges, must routinely reassure patients that obtaining ACA coverage will not be used against them in immigration proceedings. (Many immigrants, such as those with temporary protected status, work permits or other special visas are excluded from Medicaid but eligible for Obamacare; the ACA has been a boon for them.) Since the proposed change in the public-charge rule was leaked to the media last year, our family practitioners have been double-checking with their patients to ensure they are maintaining their children’s health coverage.

Any policy that results in people losing insurance has costs that ripple through whole communities, and we see those effects in our clinic. Pharmaceuticals, specialty care and hospitalizations become hard to obtain and expensive. Uninsured patients often forgo routine and essential preventive services — or vaccines for their children. Prenatal patients skip critical visits. The public health challenge increases for our whole community.

Advocates for immigrants were effective in raising the alarm: About 200,000 comments poured into Washington — the deadline for commenting was Dec. 10 — and the administration must show that it has responded to the concerns raised in those comments, a process that itself may slow the rule change.

Let’s be clear. The proposed change to the public-charge rule is not an effort to punish undocumented immigrants. It’s an attempt to prevent legal immigrants from becoming citizens. What’s more, whether by accident or, as we suspect, intent, it punishes children of immigrants who are American citizens.

This unfortunate proposal also serves as a reminder that harsh, punitive public policies can arrive without fanfare, in the form of seemingly subtle rule changes that can affect millions of people.