The U.S. Missile Defense Agency and missile defense advocates in general no doubt let out a collective sigh of relief following the successful intercept test June 22 of the Ground-based Midcourse Defense (GMD) system. It was the first kill in the last four tries for the primary U.S. missile shield, which was rushed into deployment, sidestepping many of the Defense Department’s standard development hoops, to counter a North Korean missile threat.

While the success — the first for an enhanced version of the interceptor’s kill vehicle known as Capability Enhancement 2 — is obviously a positive step, the GMD system still has much to prove as a first line of defense against an attack on U.S. territory. Overall, the GMD system has scored nine intercepts in 17 tries, for a success rate of just over 50 percent, while the new kill vehicle is one for three. 

Perhaps that’s to be expected of cutting-edge technology, and in any case the GMD is probably better than no defense at all. But no one could credibly argue that the GMD today provides reliable protection against North Korea — or any other hostile entity equipped with long-range missiles, for that matter. 

The MDA nonetheless is proceeding with a plan, announced by U.S. Defense Secretary Chuck Hagel in March 2013, to add 14 interceptors featuring the CE-2 kill vehicle to its existing GMD battery at Fort Greely, Alaska, by 2017. It’s been said here before, but it bears repeating, that the Pentagon and MDA should focus less on GMD system expansion and more on testing and reliability. It’s a better use of resources during a time of budgetary scarcity and ultimately will yield a more reliable defense capability.