Where's the Defense of Missile Defense?

I admit to being a bit bewildered by the brouhaha surrounding the U.S. desire to install a missile shield in Poland and the Czech Republic. It seems that while the media's almost exclusive focus is on the tension it's creating between the U.S. and Russia (and to a lesser extent Western Europe), the real question seems to be: why does the United States, as Robert Gates has said, feel it's necessary for the "indivisible security for the Unites States and our NATO allies" to install these missiles in the first place? Here are some plausible answers being vaguely floated around:

1) Iran and North Korean missiles pose a realistic threat to European security (as well as to U.S. troops stationed in Europe) in the next two decades, a threat which can be deterred or shot-down by a defense shield.

2) A missile defense shield serves as a political and possibly military response to Russian military moves, and threats to Western oil supplies.

The first plausible answer -- more or less Gates' -- just doesn't make sense to me. As Gates himself so proudly stated in response to Russia's exaggerated opposition, "The days of the Cold War are over and no one should seek a return to them." Exactly. If the Cold War days are over, then why are we building a missile defense shield in Eastern Europe as if Western Europe was still staring at the proverbial barrel of 45,000 nuclear warheads? If the threats to European security are so severe, then why do Europeans-- including the contrarian Polish -- fear acceptance of it will come at the expense of their security? This doesn't seem to be the old Cold War case of European governments secretly nudging us on while presenting a public face in opposition to the American military, although perhaps I'm still capable of misreading these European politicians. (They've demonstrated enough secret compliance in intra-European C.I.A. flights, illegal renditions, and torture at Guantanamo to make anyone a bit cynical.) Regardless, if the United States really wanted the E.U. on board regarding Iran and North Korea, then wouldn't it be good diplomacy to leave Europe to defend itself against the threat of a missile attack, and therefore make their need to pressure these countries all the more dire?

The second response -- the Russian one -- is equally full of holes. If the U.S. was really out to get Russia, then why would Gates fly over there and somewhat desparately (and persuasively, in this case) make his case to Putin?

I have no doubt Gates will soon get some kind of negotiated deal, and besides the barely audible cries of European Greens and leftists, no one will hear about this missile defense project again. Until then, we'll never really know why $3.5 billion was spent on an installation which in my estimation will produce only one victory: those reaping the financial and political benefits of military industrial production.