As you're such an expert on missile defense, perhaps you would be good enough to explain to us lesser mortals exactly what features of the current NMD architecture are lacking, from a technical standpoint. Please keep it non-technical.
The primary reason that NMD is a waste of money is because it is not being developed to meet real-world conditions. Every test conducted, and every test planned (including post-"deployment") do not include the types of countermeasures that any ICBM-capable state would deploy as part of a missle attack.
You would think that conducting these tests under such simplified and unrealistic conditions would at least result in a good testing track record, right? Wrong. Even the last successful test was rigged by putting a homing beacon in the simulated attack vehicle.
Another major problem with the proposed NMD solution is that it is only designed with the existing missle states in mind, and is geared to be specifically effective against their warheads. But the supposed threat is against so-called "rogue" nations who are still developing their own technology. NMD, as proposed, will not be able to intercept those weapons.
Overall, the program has another major flaw. There is no independent review process with any authority to address problems with the value and validity of the tests conducted. The program is not based on science, it is based on wishful thinking that ignores the real-world variables. After moving from an R&D scenario to a develop-to-deploy scenario, this problem only intensifies.
You cannot conduct effective research if the only people who can call the shots are advocates of the technology, or companies that stand to make a buck (actually, billions and billions of bucks) by building it.
Perhaps I did overstate my case slightly, in the sense that NMD might conceivably work is allowed to be developed as technology should be -- with scientific principles. But developed as government pork, the system has as much chance of working as a national health plan.
NMD is a black hole fiscally, and maybe a black hole technologically. As recent events have demonstrated, this may not be the time to squander money on pipe dreams and contractors who have -- I repeat -- defrauded this country on missle defense programs in the past.