John,

I have been working on SDIO/BMDO programs since 1986. But the experts here keep telling me that

a. It will never work
b. It will scare everyone so much that they will all attack us
c. It is better to insure that ANY launch/attack on us with WMD cannot be stopped, so that we can blow up the entire world instead of just shooting down a terrorist or launched in error missile.

Of course, these are all true simultaneously.