For Trump, these new salvos extend a far-reaching offensive against expertise—and the career officials who have it—that has unfolded throughout his presidency. Trump has repeatedly denigrated law-enforcement officials at the FBI, moved to evict scientists from the policy-making process, excluded the Central Command general with direct responsibility for the region from his abrupt decision to withdraw American troops from Syria, and even sparred with meteorologists over his mistaken insistence that Hurricane Dorian threatened Alabama in September.

“All presidents come into office worried that the permanent bureaucracy will be loyal to their predecessor and not to them,” says Donald Kettl, a public-policy professor at the University of Texas at Austin. “But there hasn’t been a president in memory with such a firm commitment to rooting out expertise and to relying instead on loyalists.”

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Trump’s attempt to subordinate expertise to both ideology and loyalty has perhaps been most pronounced on environmental and climate issues. The Environmental Protection Agency has disbanded or sidelined several scientific-advisory committees. It recently signaled its plan to propose a major change in federal rule-making that would make it much more difficult to use scientific research to justify new or existing regulations; the proposed rule would prevent the EPA from using any research that offered confidentiality to its subjects, as almost all major studies of the health effects of environmental threats have done. Last June, Trump signed an executive order that would require the federal government to eliminate two-thirds of its existing outside advisory committees.

These moves may fit with Trump’s broader efforts to convince his voters that they are under siege from a disdainful elite, Kettl told me, but they also expose Trump to the risk of outcomes that are difficult to defend. “Politics by slogan and base-building by convincing voters they are victims is completely different from governing. Government doesn’t work except by governing—by delivering results that citizens want, from safe drinking water to safe air travel,” he said. “That requires expertise far beyond what loyalty can deliver. And that’s what Trump’s assault of expertise puts at risk.”

Michael Kazin, a Georgetown University historian who has studied the history of populism, told me that conservative critics have denounced intellectuals as trying to impose their views on society for more than a century—at least as far back as the Progressive era and later during the establishment of the New Deal, when critics targeted Franklin D. Roosevelt’s “brain trust.” On the right, Kazin said, there has long been “a deep suspicion that those who become real decision makers in the federal government want to push their plans or ideas on ordinary Americans.”