Chairman of the Joint Chiefs of Staff General Mark Milley, the top-ranking U.S. military officer, warned Wednesday about a scary-sounding new "hypersonic" missile. "I don't know if it's quite a Sputnik moment, but I think it's very close to that," he said in an interview, referencing the famous Soviet satellite. Supposedly these weapons are faster, more accurate, and harder to detect than any previous nuclear weapon.

Milley is wildly exaggerating. As Cameron Tracy from the Union of Concerned Scientists explains in detail, a hypersonic missile is essentially little different from the intercontinental ballistic missiles (ICBMs) that have been around for decades. They are not much faster, or stealthier, or immune to detection. And while a hypersonic missile would be nearly impossible to shoot down, that is already true of ICBMs which themselves can travel at 20 times the speed of sound. Tests of anti-ballistic missile technology under ideal conditions have worked sometimes and failed sometimes, but a realistic massed attack of multiple-warhead missiles would be impossible to defend against.

Even if all the most Elon Musk-esque hype about this hyper-missile were correct, it would change nothing whatsoever about the logic of nuclear competition. Even if China actually could destroy every single American city and nuclear installation in one swift strike with 100 percent certainty, they would still face the existential threat of retaliation from nuclear submarines — not to mention nuclear winter, plus the fact that the Chinese economy would collapse instantly without America buying its exports. The logic of mutually-assured destruction which kept the USSR and America out of war for 40 years holds.