President Trump is set to unveil a plan that would make it harder for legal immigrants — those with green cards — from becoming citizens if they had ever used Obamacare, food stamps or other public assistance programs.

Team Trump’s plan is the brainchild of senior adviser Stephen Miller, the 32-year-old immigration hardliner who was also one of the principle architects of Trump’s “zero tolerance” immigration policy at the southern border, NBC News reported Tuesday.

That policy led to the forced separation of thousands of children from their parents, part of the administration’s crackdown on illegal immigration.

The administration would implement the policy by executive order, which means it would not require Congressional approval.

It’s one part of Miller’s goal of slashing the number of legal immigrants entering the US each year.

Immigrants living legally in the US who have used or whose household members have used the Affordable Care Act, children’s health insurance, welfare or other benefits could be prevented from ever getting permanent legal status or citizenship, the network reported, citing four sources familiar with a draft of the order.

Immigration lawyers and advocates said it would be the biggest change to the legal immigration system in decades, and estimate that more than 20 million immigrants could be affected.

NBC said it would impact people like Louis Charles, a Haitian green-card holder seeking citizenship who, despite working up to 80 hours a week as a nursing assistant, had to use public assistance to help his disabled adult daughter.

A spokeswoman for the Department of Homeland Security said Trump was trying to protect US taxpayers.

“The administration is committed to enforcing existing immigration law, which is clearly intended to protect the American taxpayer by ensuring that foreign nationals seeking to enter or remain in the US are self-sufficient,” she said.

“Any proposed changes would ensure that the government takes the responsibility of being good stewards of taxpayer funds seriously and adjudicates immigration benefit requests in accordance with the law.”

Democratic lawmakers slammed Miller, a former top aide to Attorney General Jeff Sessions when he was a senator from Alabama, over the report.

“This is outrageous. Legally using Obamacare or food assistance shouldn’t disqualify immigrants from becoming citizens,” said Sen. Kamala Harris of California.

“Hundreds of children still need to be reunited with their parents after the Trump administration tore them apart with their horrific border policy — now the administration wants to come after legal immigrants in America,” added Sen. Corey Booker of New Jersey.