A federal judge in South Texas has temporarily blocked President Barack Obama’s executive action on immigration, giving a coalition of 26 states time to pursue a lawsuit that aims to permanently stop the orders.

U.S. District Judge Andrew Hanen’s decision late Monday puts on hold Obama’s orders that could spare from deportation as many as five million people who are in the U.S. illegally.

Hanen wrote in a memorandum accompanying his order that the lawsuit should go forward and that without a preliminary injunction the states would “suffer irreparable harm in this case.”

“The genie would be impossible to put back into the bottle,” he wrote, adding that he agreed that legalizing the presence of millions of people is a “virtually irreversible” action.

In a statement early Tuesday, the White House said it would appeal. It defended the executive orders issued in November as within the president’s legal authority, saying the U.S. Supreme Court and Congress have said federal officials can establish priorities in enforcing immigration laws.

“The district court’s decision wrongly prevents these lawful, commonsense policies from taking effect and the Department of Justice has indicated that it will appeal that decision,” the statement said.

The appeal will be heard by the 5th U.S. Circuit Court of Appeals in New Orleans.

The first of Obama’s orders — to expand a program that protects young immigrants from deportation if they were brought to the U.S. illegally as children — was set to start taking effect Wednesday. The other major part of Obama’s order, which extends deportation protections to parents of U.S. citizens and permanent residents who have been in the country for some years, was not expected to begin until May 19.

Joaquin Guerra, political director of Texas Organizing Project, called the ruling a “temporary setback.”

“We will continue getting immigrants ready to apply for administrative relief,” he said in a statement. The nonprofit says it promotes social and economic equality for low to moderate income Texans.

The coalition of states, led by Texas and made up of mostly conservative states in the South and Midwest, argues that Obama has violated the “Take Care Clause” of the U.S. Constitution, which they say limits the scope of presidential power, and that his executive actions would be difficult to undo once immigrants started to apply for deferred action. They also say Obama’s order would force increased investment in law enforcement, health care and education.

House Speaker John Boehner said Monday’s ruling wasn’t a surprise and underscores that Obama acted beyond his authority.

Boehner said he hopes that Senate Democrats will relent in their opposition to a Homeland Security Department spending bill that overturns Obama’s action. The department’s funding expires Feb. 27 and Congress has only a few legislative days to act.

Texas Attorney General Ken Paxton called the decision a “victory for the rule of law in America” in a statement late Monday. Texas Gov. Greg Abbott, who led the state into the lawsuit when he was the state’s attorney general, said Hanen’s decision “rightly stops the President’s overreach in its tracks.”

Hanen, who’s been on the federal court since 2002 after being nominated by President George W. Bush, regularly handles border cases but wasn’t known for being outspoken on immigration until a 2013 case. In that case, Hanen suggested that Homeland Security should be arresting parents living in the U.S. illegally who induce their children to cross the border.

Congressional Republicans have vowed to block Obama’s actions by cutting off Homeland Security Department spending for the program. Earlier this year, the Republican-controlled House passed a $39.7 billion spending bill to fund the department through the end of the budget year, but attached language to undo Obama’s executive actions. The fate of that House-passed bill is unclear as Republicans in the Senate do not have the 60-vote majority needed to advance most legislation.

Among those supporting Obama’s executive order is a group of 12 mostly liberal states, including Washington and California, as well as the District of Columbia. They filed a motion with Hanen in support of Obama, arguing the directives will substantially benefit states and will further the public interest.

A group of law enforcement officials, including the Major Cities Chiefs Association and more than 20 police chiefs and sheriffs from across the country, also filed a motion in support, arguing the executive action will improve public safety by encouraging cooperation between police and individuals with concerns about their immigration status.