Donald Trump lies so frequently and so brazenly that it’s easy to forget that there are political untruths he did not invent. Sometimes, he builds on falsehoods that predated his election, and that enjoy currency among the very institutions that generally restrain his power.

That’s the case in the debate over North Korea. On Monday, The New York Times declared that “the United States has repeatedly suggested in recent months” that it “could threaten pre-emptive military action” against North Korea. On Sunday, The Washington Post—after asking Americans whether they would “support or oppose the U.S. bombing North Korean military targets” in order “to get North Korea to give up its nuclear weapons”—announced that “Two-thirds of Americans oppose launching a preemptive military strike.” Citing the Post’s findings, The New York Times the same day reported that Americans are “deeply opposed to the kind of pre-emptive military strike” that Trump “has seemed eager to threaten.”

The Times and Post are America’s best newspapers. Their reporting has frequently exposed Trump’s misdeeds. But in this case, through their language, they are abetting his duplicity and his madness. A “preemptive strike” is an attack on a country that is about to attack you. It’s the equivalent of shooting a man who is about to draw his pistol in a gunfight. That’s very different than bombing North Korea “to get North Korea to give up its nuclear weapons” and it’s very different than what the Trump administration has spent the last few months debating. For the most part, White House has been mulling a “preventive” strike: a strike aimed, not at stopping an imminent North Korean attack, but at stopping North Korea from gaining the means to launch such an attack. It’s the equivalent of shooting a man because he’s on his way to the store to purchase a pistol or because he’s at a firing range checking to see if it works.

North Korea’s equivalent of a pistol is an intercontinental ballistic missile that carries a nuclear warhead. Were Pyongyang to develop one, it would gain the capacity to incinerate parts of the United States or its Pacific territories. In recent months, the North Korean government has conducted tests apparently designed to construct such a weapon. (The Defense Intelligence Agency last month suggested that such a weapon already exists.) And Pyongyang recently suggested it might even conduct a nuclear test in the atmosphere, which would pose a threat of radiation.

This is worrisome. The world does not need more weapons capable of flattening cities on the other side of the globe. It certainly does not need them in the hands of a regime as insular, and thus prone to miscalculation, as North Korea’s. Still, there is little evidence that North Korea is planning to launch a nuclear weapon at the United States or its allies. Pyongyang has likely possessed nuclear weapons for more than a decade; it has never used them for the obvious reason that doing so would likely prompt a devastating American response. It has possessed biological and chemical weapons since the 1970s or 1980s; it has never used them against the United States or its allies either. (Though it may have proliferated them to third parties like Syria, as the U.S. did to Saddam Hussein in the 1980s, and against domestic political opponents.)

One might argue that, were North Korea about to test a nuclear-tipped intercontinental missile in the atmosphere—a test the U.S. could not be certain would fall harmlessly in the ocean rather than on Los Angeles—an American strike might legitimately be considered  “preemptive.” But the Times and Post regularly use the term to describe not just a potential American strike to thwart a North Korean atmospheric test, but any American strike aimed at delaying or destroying North Korea’s nuclear program. In April, months before North Korea suggested an atmospheric nuclear test, the Times referred to a potential American “pre-emptive strike” against North Korea’s nuclear “facilities.”

Why do these linguistic errors matter? Because they normalize something that Americans once considered monstrous. As I’ve explained in more detail elsewhere, at the dawn of the nuclear age, America’s leaders considered preventive war—war to prevent an adversary merely from gaining weapons that might shift the balance of power in its favor—both immoral and un-American. As West Point Professor Scott Silverstone details in his book, Preventive War and American Democracy, they associated it with Nazi Germany and Imperial Japan. NSC 68, the legendary document that in 1950 outlined America’s strategy for combatting the USSR, declared that, “It goes without saying that the idea of ‘preventive’ war—in the sense of a military attack not provoked by a military attack upon us or our allies—is generally unacceptable to Americans.” When he unveiled a new national security strategy in 1955, Dwight Eisenhower similarly insisted that, “[t]he United States and its allies must reject the concept of preventive war.” In explaining John F. Kennedy’s refusal to launch a preventive attack during the Cuban missile crisis, Robert Kennedy explained: “My brother is not going to be the Tojo of the 1960s.”

It was this moral revulsion, in addition to practical considerations, which led Cold War presidents to reject preventive war while Joseph Stalin and Mao Zedong—two leaders every bit as brutal and rhetorically chilling as Kim Jong Un—developed nuclear weapons. Instead, America’s leaders responded with deterrence. They warned that if the Soviet Union or China used nuclear weapons against the U.S. or its allies, the U.S. would respond in kind, thus threatening the very existence of Stalin and Mao’s regimes.

Truman, Eisenhower, and Kennedy would likely be appalled to find that in 2017, an American president seems to consider preventive war preferable to deterrence. And linguistic subterfuge helps make that possible. George W. Bush helped initiate the rhetorical deceit. In calling his attack on Iraq “preemptive,” he laundered a term for wars launched in response to imminent attack, and thus considered legitimate under international law. Tragically, his lie has stuck. During the Obama administration, the Times used the term to describe a potential Israeli strike on Tehran. Now the paper uses it to describe a potential American attack on Pyongyang. In so doing, it normalizes something Americans once rightly considered barbaric. And it makes it easier for Trump to warn that if North Korea merely threatens the United States verbally, the U.S. will launch an attack that could cost tens of thousands of lives.

“If thought corrupts language,” George Orwell famously wrote, “language can also corrupt thought.” When it comes to North Korea, Trump is not only the cause of that linguistic corruption. He’s its beneficiary too.