Washington — The Supreme Court on Monday allowed the Trump administration to enforce its most ambitious effort yet to restrict legal immigration, giving U.S. officials the green light to implement a sweeping rule that critics warn will shut America's doors to low-income immigrants and people of color.

In a 5-4 ruling, the conservative-leaning high court approved the Trump administration's request to set aside a ruling by a federal judge blocking the so-called "public charge" regulation while the merits of the case continue to be argued in lower courts. The court's conservatives, including President Trump's appointees, Brett Kavanaugh and Neil Gorsuch, agreed to allow officials to enforce the policy, while the liberal justices would've denied the administration's request

By dramatically expanding the definition of a "public charge, or an economic burden on society, the U.S. Citizenship and Immigration Services (USCIS) regulation unveiled in August gives officials more power to deny visas and green card applications from immigrants and prospective immigrants whom the government determines rely, or could rely, on certain public benefits like food stamps and government housing programs.

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For decades, the U.S. has asked most green card and visa petitioners to prove they won't be a "public charge" on the country, but the new rule scraps Clinton-era guidance that said only the use of cash benefits could be analyzed by immigration caseworkers.

The Trump administration has defended the new restrictions as a way to ensure immigrants are "self-sufficient." But opponents believe the policy is an attempt by the White House to circumvent laws passed by Congress by instituting what's essentially a "wealth test" designed to limit the immigration of poorer people from developing countries.

"If you listen to Trump talking about how he wants a points-based immigration system and wants people who are wealthier, better educated, higher skilled and not from countries he's spoken of in derogatory, profane language — this is it. This is the policy that aims to do that, without Congress approving it whatsoever," said Doug Rand, a former White House official under President Obama who co-founded Boundless, a company to help immigrants navigate the U.S. immigration system.

"It's a way to screen out people, not just from developing countries, but from any country, that the government has decided aren't wealthy enough, aren't healthy enough and don't speak English well enough," Rand added.

Soon after its final version was published last summer, the "public charge" rule was blocked in court, with one federal judge calling it "repugnant to the American dream." However, in recent weeks, circuit courts lifted three of the four nationwide injunctions against it, leaving only an order by a federal judge in New York standing.

Earlier in January, the Justice Department asked the Supreme Court to set aside the remaining nationwide injunction — a request that has now been granted. U.S. immigration officials will now be able to implement the new restrictions in every part of the country other than Illinois, where the rule is still blocked under a statewide injunction.

In a concurring opinion joined by Justice Clarence Thomas, Gorsuch expressed profound concerns about lower court judges issuing nationwide injunctions that "transcend the cases before them." He said both the government and those suing it are rushing through cases with national implications in the hopes of obtaining emergency rulings, instead of "methodically developing arguments."

"The routine issuance of universal injunctions is patently unworkable, sowing chaos for litigants, the government, courts, and all those affected by these conflicting decisions," Gorsuch wrote in his concurring opinion.

Ken Cuccinelli, an immigration hawk and the second highest-ranking official at the Department of Homeland Security, said his department is making preparations to enforce the "public charge" policy following the Supreme Court's decision.

"Self-sufficiency and self-reliance are key American values not to be litigiously dismissed, but to be encouraged and adopted by the next generation of immigrants," Cuccinelli said in a statement Monday evening. "We plan to fully implement this rule in 49 states and are confident we will win the case on the merits."

Expanding the definition of "public charge"

The term dates back to 1882, when the U.S. was trying to limit immigration from developing, non-white countries. The year it was first codified, the U.S. also enacted the discriminatory Chinese Exclusion Act, which barred the entry of most Chinese immigrants on the premise that they jeopardized "the good order of certain localities."

In the late 1990s, the Clinton administration issued guidance saying only cash benefits could be considered when determining whether an immigrant might be a "public charge." The Trump administration's policy substantially expands this term by broadening the type and amount of benefits that count against immigrants seeking to stay in or move to the U.S.

Under the new regulation, caseworkers would consider enrollment in the widely used Supplemental Nutrition Assistance Program (SNAP), certain federally funded Medicaid benefits, and a variety of forms of government-subsidized housing, including Section 8 vouchers.

Officials would deem an immigrant a "public charge" and deny the application if they determine he or she is more likely than not to use one of the considered benefits for 12 months or longer over the span of three years. On certain occasions, those deemed a "public charge" could post a bond for an amount no less than $8,100.

To determine whether prospective immigrants are likely to become a "public charge," caseworkers would also take into account their wealth, age, educational skills, English language proficiency and health. Since those expected to be affected by the rule are not eligible for most public benefits because they aren't U.S. citizens or permanent residents, critics of the regulation say it is designed to severely restrict immigration based on those factors.

"This regulation is not about public benefits, except insofar as it's scaring people to stay away from public benefits — even when they don't have to," said Rand, the former Obama official.

"What the rule really does is it imposes a 25-factor test that's never been done before, that Congress has never authorized, that is going to make it less likely for someone to get a green card based on their age, their income, their heath, the number of children they have, whether they have a mortgage or student loans and a whole bunch of other things that have nothing to do with public benefits," he added.

Immigrant advocates are concerned about the effects the rule could have on people who are technically not subject to it. Researchers have documented a "chilling effect" stemming from the proposed changes that have prompted some fearful immigrant families, including families that include U.S. citizens, to drop out of benefits programs.

The stringent requirements proposed by the "public charge" rule are not the only moves the administration has taken to impose limits on legal immigration.

In October, the White House issued a proclamation allowing the government to reject visa applications from would-be immigrants it determines won't be able to cover their medical costs. The plan, which is still being held up in court, could deny entry to approximately 375,000 prospective immigrants each year, according to an estimate by the nonpartisan Migration Policy Institute.

A proposed rule by USCIS published in November would hike petition fees for immigrants seeking U.S. citizenship, for young undocumented immigrants known as "DREAMers" trying to renew protections from deportation and for victims of crimes who are seeking to stay in the country through their assistance to law enforcement. The proposal would also make the U.S. one of only four nations that require asylum-seekers fleeing persecution to pay a fee to file affirmative requests for protection.

Jan Crawford contributed reporting.