A federal court in Texas on Friday temporarily blocked the Trump administration from building a border wall and other infrastructure across the state's Big Bend region, handing a victory to opponents who have pushed back against one of President Donald Trump's signature campaign promises.

The planned projects are part of a $46 billion effort by the Trump administration to line the southern border with a mix of 30-foot-tall steel walls, vehicle barriers, roads and surveillance technology. The proposal has united landowners, businesses and environmentalists across the region in opposition.

Ruling on Friday, Judge Kathleen Cardone found that the plaintiffs were "likely to succeed on the merits of at least one of the claims in suit, that there is a likelihood that they will suffer serious, irreparable harm without an injunction, and that the balance of the equities and the public interest weigh in their favor."

Those findings track the showing plaintiffs must generally make to obtain a preliminary injunction — an interim step that keeps construction on hold while the case moves toward a final ruling on the claims themselves, meaning the broader legal fight over the wall remains unresolved.

U.S. Customs and Border Protection defended the project in a statement on Friday. "We stand by our assessment and remain confident in our legal authorities to secure the border while preserving the unique landscape the Big Bend region," the agency said. "We are working with the Department of Justice on next steps." The Department of Homeland Security did not immediately respond to a request for comment.

Remote terrain at the center of the dispute

The judge's ruling covers Big Bend National Park, where resistance to the wall had already prompted the administration to briefly pause construction. Opponents of the project have argued that the 500-mile-long Big Bend region of Texas is so remote and its landscape so rugged that it serves as its own deterrent to illegal immigration. They also contend the administration violated the law when it issued a swath of waivers allowing it to bypass numerous regulations in order to speed up border wall infrastructure projects. Waivers of that kind draw on the federal REAL ID Act of 2005, which grants the Homeland Security secretary authority to set aside laws that would otherwise apply to border barrier construction — power that successive administrations have used to waive environmental and other requirements along the border.

The lawsuit was brought by an environmental organization, advocates for a historic church in Ruidosa and a river guide, who argued that the Department of Homeland Security was wrong to circumvent regulations meant to protect the environment, culture and archaeology of regions like the Big Bend area.

Laiken Jordahl of the Center for Biological Diversity, which brought the suit, called Cardone's ruling a "total victory." "The bulldozers are going to be sent packing until she rules on the merits," Jordahl said. "This is such a historic day for Big Bend and for Texas and the Constitution."

Bipartisan opposition inside the national park

The court's decision comes just weeks after the administration erected the first border wall panels in the Big Bend sector in mid-September. The project has sparked bipartisan opposition, much of it focused on CBP's plans inside Big Bend National Park, which is prized for its scenic landscapes, limestone cliffs and crystal clear night sky views.

When bulldozers were spotted clearing land in the park in August, the activity triggered widespread calls from both Republicans and Democrats for the administration to stop. CBP subsequently paused all activity there, but that pause expired earlier this week. The administration has said it is reevaluating its plans for the national park, though it has not yet said what it intends to do.

Park advocates on Friday welcomed the ruling while urging the administration to repair the damage already done to Big Bend National Park and to develop alternative plans. "Big Bend is no place for border barriers. It's time for the administration to come to the table with the border communities that know Big Bend best, repair the damage from this ill-conceived project, and find new solutions," said Tiernan Sittenfeld, President and CEO of the National Parks Conservation Association, in a statement.

Injunction reaches beyond the park

The judge's ruling also extends to areas upriver and downriver from the national park, where CBP has planned a range of border infrastructure projects that would largely require construction across privately owned land. The government has been working to obtain permission from local landowners to survey and build on their property, but in a recent court filing it said it was prepared to refer some cases to the Justice Department in which it had been unable to secure that permission. Referrals of that kind typically lead to eminent-domain proceedings, in which the government asks federal courts for access easements when voluntary agreements cannot be reached — a dynamic that has long accompanied border barrier construction on private land in Texas.

This story was originally featured on Fortune.com.

Additional coverage: AP News, AP News.