You gotta love the moniker of the retired Air Force three star: “Fig Leaf”. 

Brings to mind the ineffective, kick the can, foreign policy approaches to the DPRK problem of both Slick Willy and that America hating mulatto who did his level best to destroy (“transform”) our country in a mere 8 years.

More important is the perspective of Lt. Gen Leaf, looking at the situation not from our side but from that of Pyongyang:  “Improving Hawaii’s defenses complicates the (North Korean) attack calculations and puts Kim Jong Un on notice that the U.S. is not going to sit idly by under their threats.

A missile defense architecture need not be perfect to introduce an element of doubt into even the most fanatic would be button pusher, to wit: “What if my birds don’t hit the DGZs or for some reason malfunction because of a near intercept?”. 

The advantage of our having even and imperfect defense in depth ABM surveillance/tracking/intercept capability is that we can buy time which is precious.