The message of the world's top public intellectual does not vary, incidentally, in character or accuracy. Here's an article from Noam Chomsky last month in which he argues: "It is well known on all sides that missile defense is a first strike weapon."
See what I mean? It is not well known at all, for the uncomplicated reason that it isn't true; yet the affectation of exposing official deceit appeals to a certain constituency, especially those of college age.
Those who argue for a missile defence system (such as Michael O'Hanlon and James Lindsay of the Brookings Institution) acknowledge that no arrangement could be 100 per cent reliable and that a determined adversary could in any case construct countermeasures, such as using decoy warheads in addition to real ones. The logic of missile defence is rather that, faced with an adversary with a limited nuclear arsenal - as is likely to be the case with North Korea and Iran in the near future - then something short of complete reliability might nonetheless be effective. Missile defence would thereby strengthen deterrence.
When President Reagan proposed his own Strategic Defense Initiative in 1983, he conceived it (absurdly) as a means of securing the abolition of nuclear weapons. SDI would make nuclear weapons redundant, he believed. To that end, Reagan proposed sharing the technology with the Soviet Union. (This is confirmed by the transcripts of his conversations with Gorbachev at the Reykjavik summit in 1986: "We are ready to share our accomplishments in strategic defense.") I recount this because US nuclear policy has by no means been the consistent one that Chomsky imagines. On two occasions in the nuclear age - the Acheson-Lilienthal and Baruch Plans of 1946, and Reagan's proposals on SDI - the US has even proposed abolishing a technological monopoly that it then enjoyed.