President Trump is getting serious about going after immigrants who use public benefits.

In a presidential memorandum issued Thursday, Trump announced he will direct federal agencies to enforce a longstanding rule requiring the sponsors — usually U.S. citizen family members — of immigrants to reimburse the government for any public benefits they use, including Medicaid, SNAP, TANF, and the federal Children’s Health Insurance Program (CHIP).

“Financial sponsors who pledge to financially support the sponsored alien in the event the alien applies for or receives public benefits will be expected to fulfill their commitment under law,” Trump said in the memo.

The memo hinges upon a 1996 welfare reform law enacted by former President Bill Clinton, which the White House claims has not been enforced consistently. The provision requires sponsors to sign a document reaffirming they are responsible for an immigrant’s financial needs and that if they apply for any public assistance programs, the sponsor must reimburse the government. If the sponsor is unable to pay the bill, that debt would be referred to a collections agency.

Trump has directed his administration to, over the next 90 days, develop rules by which the government can determine which sponsors are required to pay back the federal government for each dollar of means-tested federal aid provided to a non-citizen. If a sponsor is found to be delinquent, they could lose their ability to sponsor, meaning thousands of families could be separated.

The directive is still lacking on key details, including how it will be implemented. It will likely be extremely complicated, considering it spans multiple agencies, like the Department of Agriculture, the Department of Homeland Security, the Social Security Administration, and more. Additionally, local jurisdictions that distribute these resources would also have to be looped in.

Because sponsors are typically relatives of immigrants arriving to the United States to reunite with family, this latest announcement from Trump affirms the administration’s shift away from family-based migration and towards a merit-based immigration system. Last week Trump unveiled an immigration plan crafted by his son-in-law and senior adviser, Jared Kushner, that would prioritize “high-skill immigrants” and reduce the number of family-based visas and green cards.

The administration is moving fast on implementing a series of rules that target immigrants for using various public benefits.

In early May, the Department of Housing and Urban Development (HUD) formally submitted a proposed rule to evict all undocumented immigrants from public housing. The plan would displace more than 55,000 children — all of whom are U.S. citizens or legal residents. Now that the rule has been formally introduced in the federal register, the public will have 60 days to submit comments for the record.

Last year, the administration proposed a rule that would label many low-income immigrants who use public benefits a “public charge” on society and prevent them from obtaining permanent residency. The rule was pushed by White House senior adviser Stephen Miller, who has been at the forefront of influencing Trump’s hardline position on immigration ahead of the 2020 election.

Like the public charge proposal, the memo announced Thursday is not going to be immediately implemented. It also does not apply to non-citizen immigrants already in the United States. That hasn’t prevented many immigrants, however, from dropping out of or not applying for public assistance programs for fear of being denied permanent residency.

A study from the Urban Institute published this week found that in 2018, 17.4% of adults in immigrant families with kids reported they or someone in their family avoided programs like SNAP or subsidized housing because of green card concerns.