Climate-change deniers go to great lengths to convince the public that there’s a legitimate scientific debate about whether humans are the main cause of global warming, but the Trump administration took this pathology to another level last week: Scott Pruitt, the head of the Environmental Protection Agency, plans to form a group to question the merits of climate science. Quoting a senior administration official, E&E News reported that the EPA group “will use ‘red team, blue team’ exercises to conduct an ‘at-length evaluation of U.S. climate science.’” Activists and journalists expressed the requisite alarm.

The offhand climate science denialism of the Trump administration is becoming more organized, potent and dangerous. https://t.co/wJamk1m8ys pic.twitter.com/sJNUK3o6oh — John Upton (@johnupton) June 30, 2017

This new group is just the latest tactical move in what many, including the New York Times’ editorial board, have dubbed the Trump administration’s “war on science.” Pruitt denies the scientific fact that carbon emissions drive global warming. He removed accurate scientific information about climate change from the EPA’s website. He fired almost everyone who currently serves on the Board of Scientific Counselors, which ensures the integrity of the agency’s main science division, and may fill those vacancies with representatives from polluting industries. Meanwhile, on Capitol Hill, Texas Senator Lamar Smith has proposed two bills: one to overhaul the makeup of the EPA’s Scientific Advisory Board (SAB), which evaluates the science behind agency regulations; and another to restrict what kind of science the EPA can use to create regulations.

Pruitt and his allies clearly want to undermine basic climate science at the EPA, but it’s important to understand why. It’s not simply that Pruitt wants to mold the agency in his image. It’s because the best available science bolsters the Obama-era policies he wants to repeal, and it will likely show that Pruitt’s own policies would endanger the public—even causing preventable deaths due to pollution and higher temperatures. Pruitt and his allies want to avoid such politically damaging scientific conclusions, so they’re trying to cripple the science itself.

To understand why Pruitt is so eager to change scientific review at the EPA, look at the Waters of the United States Rule. This week, Pruitt moved forward with his long-expected move to repeal the Obama-era regulation, which dramatically expanded Clean Water Act protections for small bodies of water. It’s a controversial rule—more so, perhaps, than any environmental regulation of Barack Obama’s presidency.

But Pruitt faces a rhetorical obstacle. In 2014, the EPA’s Scientific Advisory Board released a 103-page review of the science behind the rule, and determined that it was sound: Obama and his allies were scientifically correct when they argued that protecting these waters would have a real impact on protecting human health. Specifically, the report confirmed that the small streams and wetlands WOTUS sought to protect “exert strong influence on the physical, biological, and chemical integrity of downstream waters.” In other words, reducing pollution from small bodies of water has tangible impacts on the quality of drinking water from larger, connected bodies.