A U.S. judge in Texas on Thursday ruled against President Joe Biden's program offering a path to citizenship for certain immigrant spouses of U.S. citizens, a blow that could keep the program blocked through Biden's final months in office.

U.S. District Judge J. Campbell Barker found the program exceeded Biden's executive authority. The program offers a path to citizenship to about 500,000 immigrants who entered the U.S. illegally if they are married to U.S. citizens.

The initiative, known as Keeping Families Together, launched in August but was blocked days later by Barker, who left it frozen while he considered a legal challenge brought by Texas and a coalition of U.S. states with Republican attorneys general.

Biden, a Democrat, announced the program in June before dropping out of the presidential race and paving the way for Vice President Kamala Harris to face Republican Donald Trump, an immigration hard-liner.

Trump defeated Harris in Tuesday's election and is expected to launch a wide-ranging immigration crackdown that would likely include rolling back Biden's initiative for immigrant spouses, which the Trump campaign called a "mass amnesty" that would encourage illegal immigration.

Americans see immigration as the most pressing issue for Trump to address when he takes office in January, and a large majority believe he will order mass deportations of people living in the U.S. illegally, a Reuters/Ipsos poll that closed on Thursday found.

The Biden administration could appeal Thursday's court ruling. The White House did not immediately respond to a request for comment.