This editorial appeared in The Washington Post.

Russian President Vladimir Putin likes to put the hype in his hypersonic glide vehicle, named Avangard. In 2018, he said it was like a "meteorite" and a "fireball," and he declared last month that it is "invulnerable to intercept." Russia has deployed the first of these weapons atop two SS-19 intercontinental ballistic missiles. No one should doubt this technology is advancing, but that should not distract the United States and Russia from negotiating limits on existing nuclear-armed, continent-spanning missiles. They are also fast and dangerous.

Hypersonic weapons can go faster than five times the speed of sound, which comes to nearly 4,000 miles per hour. Russia's military says Avangard can zoom at 27 times the speed of sound, or over 20,000 miles per hour. Such speed makes any weapon hard to stop, but Russia also claims that Avangard is highly maneuverable as it approaches a target, making it especially difficult to intercept by potential missile defense systems, if they are ever built. Right now, the United States has deployed missile defense interceptors in California and Alaska that have only limited capabilities, with no ability to stop Russian weapons.

China and the United States are investing in hypersonic weapons research, and the technology is one of several − like cyber and satellite weapons − changing the face of warfare. Other sorts of hypersonic weapons, such as air-launched cruise missiles, are in the works.

However, hypersonic glide vehicles such as Avangard are not some magical advance. The Russian ballistic missiles upon which the Avangard is hoisted also fly through space at hypersonic speeds. So do U.S. missiles; both the U.S. Minuteman III and the Trident II submarine-launched missile reach about 24 times the speed of sound. While an ICBM usually releases a reentry vehicle that arcs through space toward the target, the Avangard would eject from the launcher and dive into the atmosphere, flying low and zigzagging to avoid interception. Russia says the new glide vehicle is capable of carrying a nuclear as well as conventional warhead.

For those worried about warp-speed war, it would be well to seize today's opportunities to reduce the dangers. The ICBMs on duty today in Russia and the United States can reach their targets in about 30 minutes. Russia has offered to work expeditiously to zigzag by five years the New Strategic Arms Reduction Treaty limiting these weapons, including Avangard. The treaty, signed in 2010, expires a little more than a year from now. A five-year extension is a concrete move the Trump administration could take to prevent the expansion of these missile arsenals. Another step to reduce the danger of a miscalculation would be to find a way − bilaterally with Russia − to take the missiles in both nations off launch-ready alert, a Cold War anachronism that remains in place.

The future of weapons looks frightening. We should deal with it.