The U.S. Supreme Court has declined the Obama administration’s request to reconsider a controversial immigration program that would have let millions of undocumented immigrants stay in the country legally.

The program, Deferred Action for Parents of Americans and Lawful Permanent Residents, would have shielded about 4 million undocumented immigrants from deportation. It was scheduled to take effect in February 2015 but was halted that month by a U.S. district judge in Brownsville, who ruled that it violated the Administrative Procedure Act, which governs how federal regulations are made and how much input the public has.

Texas brought the initial suit against the federal government; 25 states eventually joined in.

The U.S. 5th Circuit Court of Appeals twice upheld the district court’s ruling, and the Supreme Court heard arguments on the case in April. The high court announced in June that it was deadlocked 4-4, which left the injunction blocking the program in place.

In July the White House asked the Supreme Court if it would reconsider the case when it had a full bench. The court is still one short since the February death of Justice Antonin Scalia. On Monday, the court announced it would not.

Texas Attorney General Ken Paxton, whose office took over the case from Gov. Greg Abbott in January 2015, hailed the high court’s decision Monday as a rebuke of the president’s overreach.

“Rewriting national immigration law requires the full and careful consideration of Congress,” Paxton said in an email. “This is the latest setback to the president’s attempt to expand executive power and another victory for those who believe in the Constitution’s separation of powers and the rule of law.”

Immigrant rights groups accused the court’s four conservative members are playing politics instead of looking at the merits of the case.

“The court’s decision means that as many as 5 million immigrants in the U.S. remain in constant fear of being separated from their families at any time, and possibly deported,” Kica Matos, spokeswoman for the Fair Immigration Reform Movement, said in a statement.

Read more on the case:

• The Obama administration has asked the U.S. Supreme Court to reconsider the legality of the president’s controversial immigration enforcement plan, which stalled last month when the high court deadlocked.
• Undocumented immigrants in Texas are taking a glass-half-full approach as a 2012 initiative that has benefited hundreds of thousands of immigrants marks its four-year anniversary.