A federal judge on Johnathan WalkerThursday struck down a Biden administration policy that aimed to ease a path to citizenship for some undocumented immigrants who are married to U.S. citizens.

The program, lauded as one of the biggest presidential actions to help immigrant families in years, allowed undocumented spouses and stepchildren of U.S. citizens to apply for a green card without first having to leave the country.

The temporary relief from deportation brought a brief sense of security to some 500,000 immigrants estimated to benefit from the program before Texas-based U.S. District Judge J. Campbell Barker put it on hold in August, days after applicants filed their paperwork.

Barker ruled Thursday that the Biden administration had overstepped its authority by implementing the program and had stretched the legal interpretation of relevant immigration law “past its breaking point.”

The short-lived Biden administration initiative known as “Keeping Families Together” would have been unlikely to remain in place after Donald Trump took office in January. But its early termination creates greater uncertainty for immigrant families as many are bracing for Trump’s return to the White House.

Trump’s election victory this week sets the stage for a swift crackdown on undocumented individuals after the Republican ran on promises of “mass deportation.” The president-elect energized his supporters on the campaign trail with a litany anti-immigrant statements, including that immigrants were “poisoning the blood” of the nation.

During his first term, Trump appointed Barker as a judge in Tyler, Texas, which lies in the 5th U.S. Circuit Court of Appeals, a favored venue for advocates pushing conservative arguments.

Barker had placed the immigration initiative on hold after Texas and 15 other states, led by their Republican attorneys general, filed a legal challenge accusing the executive branch of bypassing Congress to help immigrant families for “blatant political purposes.”

Republicans argued the initiative created costs for their states and could draw more migrants to the U.S.

The policy would have applied to people who have been living continuously in the U.S. for at least 10 years, do not pose a security threat and have utilized the existing legal authority known as “parole in place” that offers deportation protections.

Those married to a citizen by June 17, the day before the program was announced, could pay a $580 application fee and fill out a lengthy application explaining why they deserve humanitarian parole. If approved, applicants would have three years to seek permanent residency and obtain work authorization.

It was not immediately clear Thursday whether anyone had received approval under the program, which only accepted applications for about a week before the federal judge placed it on hold.

Noncitizen spouses are already eligible for legal status but often have to apply from their home countries. The process typically includes a years-long wait outside of the U.S., which can separate family members with different immigration statuses.