In a move that has reignited debate over U.S. border policy, President Donald Trump has ordered the entire southern border wall to be painted black, aiming to deter migrants from crossing and to extend the structure’s lifespan. The announcement, made by Homeland Security Secretary Kristi Noem on August 19, 2025, marks the latest chapter in Trump’s ongoing efforts to clamp down on illegal immigration.
Standing near the border in Santa Teresa, New Mexico, Secretary Noem told reporters, “We are going to be painting the entire border wall black.” She explained that the directive came directly from President Trump, who believes the dark paint will make the steel bollards unbearably hot under the desert sun, thus discouraging migrants from attempting to climb the 30-foot barrier. Noem herself applied paint to a section of the fence during her media appearance, underscoring the administration’s commitment to the project.
Noem did not disclose the projected cost or timeline for painting the wall, but her presence at the site and hands-on demonstration signaled the administration’s determination to see the initiative through. On social media, she stated that the new coating would be “so hot to the touch that criminal illegal aliens won’t even try.” According to Bloomberg, the administration expects the black paint to slow rust and extend the steel’s lifespan, providing a practical benefit alongside its intended deterrent effect.
The idea of painting the border wall black is not entirely new. Back in 2020, during Trump’s first term, officials tested black paint on certain sections of the structure. However, experts remain skeptical about the efficacy of this tactic. Richard Duncan, a mechanical engineer and building scientist, told McClatchy News, “The primary source of heat gain for this wall is infrared solar radiation. In general, darker surfaces absorb more heat due to higher emissivity—the measure of a material’s ability to absorb and emit infrared energy.” Yet, Duncan cautioned that the impact might be minimal. “If the steel wall is left unpainted, it will oxidize or rust, a process that increases its emissivity. In contrast, black paint will deteriorate under prolonged sun exposure, becoming gray and decreasing its emissivity. Therefore, the net thermal impact of painting the wall black versus allowing it to rust is minimal.”
Duncan also noted that in arid climates like the U.S.-Mexico border region, low moisture levels naturally lead to low corrosion rates for steel. “Given these factors, applying a protective coating may not be economically or functionally justified,” he concluded. This sentiment is echoed by others who question whether the black paint will actually make the wall significantly hotter or more difficult to climb.
Beyond the scientific debate over heat, many immigration experts point out that most migrants don’t climb the wall at all. Tony Payan, director of the Center for the U.S. and Mexico at Rice University’s Baker Institute for Public Policy, told McClatchy News, “The number of individuals that are crossing over the fence is very small.” Douglas Massey, an emeritus professor of sociology at Princeton University, added, “Most of the border is unwalled and migrants just go around the fortified zones or enter surreptitiously through ports of entry.”
The U.S.-Mexico border stretches about 1,954 miles, but only roughly 500 miles feature physical barriers, primarily in California, Arizona, and New Mexico, according to a 2020 analysis by BBC. Since 2021, an additional 50 miles of wall have been constructed in Texas, with more planned elsewhere. The barriers themselves vary in design, from tall steel bollards to mesh and chain-link fencing, as reported by the U.S. Customs and Border Protection.
Julia Gelatt, associate director of the U.S. Immigration Policy Program at the Migration Policy Institute, explained that many migrants enter the U.S. between sections of fencing, or with the help of smugglers, through tunnels, holes cut in the fence, or by climbing over. “I suspect that black paint would not be a big factor in deterring migrants who are set on crossing the border into the United States,” Gelatt said. A USA Today analysis found that, in 2022, nine people died falling from the border fence and several hundred more were injured, further highlighting the dangers some migrants face.
Despite the skepticism, the Trump administration has pressed ahead with its border enforcement strategy. In Santa Teresa, about seven miles of new barriers are currently being installed, filling in previously open gaps. Congress has approved nearly $47 billion for continued border wall construction and maintenance, according to Bloomberg, providing a fresh stream of funding for Trump’s plans. The recently passed “One, Big Beautiful Bill” allocates significant resources to finish the border wall system started during Trump’s first term. When asked about the cost of the paint project, a Department of Homeland Security spokesperson declined to provide an estimate, citing an active procurement process. However, a 2020 Washington Post analysis pegged the cost of painting the entire wall black at around $500 million.
The clampdown is also visible in the increased military presence along the border. In Sunland Park, New Mexico, residents have grown accustomed to the sight of a Stryker armored combat vehicle perched on a mesa overlooking Mexico, an American flag fluttering from its rear. Thousands of active-duty troops are deployed under U.S. Northern Command, authorized to briefly detain and search migrants in newly designated “National Defense Areas” near the boundary. The Pentagon describes these areas as extensions of U.S. military installations, further underscoring the administration’s security-first approach.
Local residents have mixed reactions. Lydia Pinon, who lives in the area, told Bloomberg, “At night there’s a lot of lights and noise. I think it’s just there to scare the people,” referring to the armored vehicle. The heightened enforcement measures have coincided with a dramatic drop in border crossings. In June 2025, just over 6,000 people were apprehended while trying to illegally cross into the U.S. at the southern border, the lowest monthly figure ever recorded, according to CBS News. By contrast, during President Biden’s term, apprehensions often exceeded 6,000 per day, sometimes topping 10,000.
With border arrests plunging to levels not seen in decades, some experts question the necessity of additional deterrents like painting the wall. “The number of individuals showing up at the border is already low,” Payan noted, suggesting that painting the entire border wall “seems like a waste of resources to deter probably a few hundred individuals.”
As the Trump administration continues to double down on physical and visual deterrents at the border, the debate over their effectiveness rages on. Supporters argue that every added obstacle helps, while critics point to scientific and logistical doubts, as well as the significant financial cost. For now, crews in New Mexico are rolling out paint, one section at a time—an unorthodox solution in a long-running and contentious national conversation.
