Arthur Herman, a Senior Fellow at the Hudson Institute wrote of an interesting idea over the weekend in The Wall Street Journal.  The title of his article explains the idea: There’s a Way to Stop a North Korean Missile Attack.

He wrote about a means of implementing a boost-phase missile defense system.  The advantages of intercepting a ballistic missile during its boost phase—the phase immediately after missile launch—are several

• the missile’s first stage, its booster, is the hottest of them all, and so the easiest to detect
• the missile is moving at its slowest speed, especially compared to the missile warhead’s reentry speed, which is enormous
• the booster is very large, especially compared to the warheads and decoys that are the missile’s payload, and so again very easy to detect
• the boost phase is the least cluttered detection environment—those warheads and decoys, and any associated electronic countermeasures, have not yet been deployed, so there’s less need to sort the defense system’s target out of the clutter
• the boost phase occurs at the earliest stage of the missile’s flight (of course), and so there’s both far more reaction time and increased opportunity to reservice the missile or to go after deployed warheads in the event of a boost phase miss.
• debris from a successful intercept would fall closer to the launch facility as opposed to a terminal phase intercept, which debris would fall closer to the missile’s intended target, and with potentially catastrophic result if the terminal intercept occurs late (and at commensurately lower altitude) in the phase

Herman then pointed out that we have the technology.

A BPI [boost phase intercept] would be launched not from a ground- or sea-based system like THAAD or Aegis, but from an unmanned aerial vehicle waiting at 55,000 feet and equipped with infrared sensors that will detect missile launches from 350 miles outside North Korean airspace. Even a submarine-based missile could be detected minutes after launch, something neither THAAD nor Aegis can do currently.

The aerial vehicle would be equipped with a conventional antimissile missile of 225 kilograms, more than enough firepower to bring down even a large intercontinental ballistic missile.

And

There are already American-built unmanned aerial vehicles capable of carrying up to four interceptor missiles of this size, while conventional aircraft have successfully done BPI tests using missiles of this type. Putting those vehicles on a rotating patrol off the North Korean coastline would mean continuous surveillance and detection.

As implied above, Herman suggested deploying such a system to defend against a nuclear attack by northern Korea.  It occurs to me, though, that we should expand the deployment.  We should operate such a BPI system out of Alaska, Greenland, and eastern Europe, to defend against a Russian attack.  We should operate such a system out of Vietnam (a potential ally, and useful at least until we can recover the Philippines as a reliable ally) and enough additional locations in Japan to handle the People’s Republic of China, as well.  We should operate such a system out of southern Europe and Israel for the benefit of Iran.  And we should operate such a system along each of our coasts to handle someone’s submarine launches.