Last month, after thirty years of work from a broad coalition of conservationists, business leaders, and politicians, El Paso’s Castner Range was finally granted permanent federal protection. “When I was elected to Congress, the community let me know they expected this would be a priority,” says U.S. Representative Beto O’Rourke, the Democratic hopeful from El Paso who is currently campaigning to unseat Senator Ted Cruz. “It’s an important victory, but it’s just one battle in the effort to open this land to the public.” In a moment when the future of public land seems perilous, O’Rourke and other advocates for the preservation of the the low-lying eastern slopes of the Franklin Mountains received help from an unlikely source: the Trump administration.

Like the Chisos Mountains in Big Bend, the Franklin Mountains rise from the desert floor to create an impressive sky island that offers plenty of outdoor activities for birdwatchers, mountain bikers, and peak baggers. Most of Franklin’s peaks have been protected since 1981, when Texas Parks and Wildlife acquired 24,000 acres within El Paso city limits—making it the largest urban park in the United States. But the Castner section, a rugged patch of the Chihuahuan Desert, was left out of the park plan.

The 7,081-acre Castner Range wasn’t part of the initial acquisition due to its past use as a U.S. Army artillery range (it’s a “range” because of its prior use for military target practice, not a signifier of a mountain range). From 1939—when most of Castner was purchased by the Department of Defense—through 1966, soldiers from Fort Bliss used the area for target practice for anti-tank guns. When military operations ceased, West Texas environmentalists hoped that the land—which hosts the easternmost blooms of California poppies as well as the only Texas zone for the rare Southwestern barrel cactus—might be transferred from the federal government to Texas Parks and Wildlife. But liability concerns over the removal of live munitions and a lean state parks budget prevented the Texas Parks and Wildlife’s takeover campaign from gaining traction.

So the military remained in control of the range, which meant development remained a threat. While he was a member of the El Paso City Council in 2006, O’Rourke participated in a unanimous vote to stop a proposal for an office complex that would have paved over 2,000 acres on the south side of the Castner Range. After O’Rourke unseated Representative Silvestre Reyes in 2012 and headed for Washington, D.C., he began laying a legislative path to permanently defend the ecological and cultural resources of the former firing range. This past June, O’Rourke who serves on the House Armed Forces Committee, added a provision to the 2017 National Defense Authorization Act to ensure that there will be no new roads or any sort of building on the range. “This is an important step toward conserving this national treasure, which includes some of the most unique cultural, historical, and natural resources in Texas,” O’Rourke wrote on Facebook in June.

In December, President Donald Trump signed the NDAA, green-lighting $700 billion in military spending and, more than likely unwittingly, protecting the Castner Range. It was an unexpected win for advocates, who had earlier pinned their hopes on the range being named a national monument. At the end of 2016, author and presidential historian Douglas Brinkley, who works at Rice University, wrote a New York Times editorial urging President Barack Obama to make the Castner Range a national monument. O’Rourke, at first following Brinkley’s lead, only added the NDAA provision after his own failed attempt to persuade the former president.

But had they been successful, Castner might have been in the crosshairs of a White House intent on reversing many Obama-era accomplishments. “We worked the hell out of the Obama administration to get monument status. But if this had been the last thing for them to accomplish, we might have seen a reversal,” O’Rourke says.

President Trump has taken a hatchet to several national monuments protected by Obama under the Antiquities Act, including slashing the 1.3 million-acre Bear Ears National Monument in Utah by 83 percent. Trump also shrunk the 1.9 million-acre Grand Staircase-Escalante National Monument, created by President Bill Clinton, by half. These moves represent the largest reversal of federal land protection in U.S. history. The Interior Department also aims to reclassify the Organ Mountains-Desert Peaks in New Mexico—established in 2014, just 50 miles north of El Paso—to allow gas and oil drilling, and redraw the boundaries of Gold Butte National Monument in Nevada, which Obama designated in 2016. “The Antiquities Act does not give the federal government unlimited power to lock up millions of acres of land and water,” Trump said in a December press release. “It’s time we ended this abusive practice.”

For now, advocates are celebrating, even if there is still work to be done. “The Castner Range is not a national monument, but it’s a big step in the right direction,” says El Paso native Angel Peña, who works with the Colorado non-profit Conservation Lands Foundation (the foundation is suing the Trump administration over the Grand Staircase-Escalante). “We don’t see it as a blue or red issue. This is a special place that should be protected.”

With the assurance that the land cannot be sold for development, groups like the Frontera Land Alliance are continuing their push for the entirety of the Castner Range to open to the public. Back in 1979, the Texas Legislature passed a measure that provided for the transfer of the land to Texas Parks and Wildlife, but the Army has not finished clearing unexploded ordinances from the eleven-square-mile parcel. Cleanup is scheduled to continue until at least 2023 before a final decision about land access or its eventual transfer to the state can be made. More than 600 potentially deadly munitions have been removed from the site, according to a report from the Army Environmental Command in San Antonio. For now, the only area open for visitation is a small network of trails behind the El Paso Museum of Archeology off Loop 375.

At Franklin Mountains State Park headquarters, superintendent Cesar Mendez says he appreciates that the Castner Range could expand the park by nearly 30 percent, though he is mindful that the ultimate approval for its adoption rests with the Texas Parks and Wildlife Commission in Austin. “With the passage of this legislation, it will not be sold for development,” Mendez says. “So we are clearly in the game, and if the land is clean and safe for the public, we are definitely interested.”

For his part, whether its a national monument or a state park expansion, O’Rourke remains committed to a future when Texans will once again be able to set foot on the Castner Range. “We still face the larger challenge of making sure there is access for the American public and visitors from around the world who want to understand the American story,” O’Rourke says. “Whatever role I play next, whether as U.S. senator or private citizen, I will do what it takes to help make sure that happens.”