The high court's action allows work to proceed on a signature initiative of President Donald Trump, who has long promised to build a wall along the entire southern border. Republicans in Congress funded the project with $46 billion last summer, and U.S. Customs and Border Protection has been rapidly erecting 12 miles of border barriers per week across the border, according to the government.

The administration has accelerated construction by issuing sweeping waivers that bypass environmental and other regulations that have historically slowed major infrastructure projects. In the Big Bend, the plan calls for 30-foot-tall steel walls in some areas, along with vehicle barriers and new roads.

Opponents from both parties have rallied against the project, contending that the barriers are a waste of money that threatens the local economy and way of life in a region with historically low rates of illegal immigration. They argue that surveillance technology such as drones could accomplish the job more effectively.

A federal judge in Texas sided with the opponents, finding that Congress likely had not clearly authorized such broad waivers for an area with the southern border's lowest rate of migrant apprehensions. The judge ordered an immediate halt to all construction-related activity in the area, which includes Big Bend National Park as well as land along the river in state and private hands.

The Trump administration filed an emergency appeal, asserting that illegal border crossings and drug seizures occur in Big Bend and that traffic could be funneled there if a gap in the wall exists. Federal attorneys argued that the project is necessary for national security.

The Supreme Court agreed that the law sharply limits judges' power to intervene when the federal government determines that speedy border barrier construction is necessary. The majority paused the lower court's decision, with Justice Ketanji Brown Jackson dissenting.

The ruling means construction crews can return to the Big Bend, a remote and ecologically sensitive region that includes the national park and stretches of the Rio Grande. Local officials and environmental advocates have warned that the wall could harm wildlife corridors, damage tourism, and alter the character of a region that relies on its natural beauty to attract visitors.

The decision is the latest development in a long-running legal and political battle over border policy, with the Supreme Court's conservative majority again siding with the administration's push to expedite wall construction. For residents of the Big Bend, the ruling removes a temporary reprieve and raises questions about how quickly the steel barriers will rise across a landscape many had hoped to protect.