What if it does work?
I don't just mean works pretty good, I mean works according to the wildest dreams of Reagan; a shield that pretty much renders nuclear weapons utterly pointless, as it can be used on the coasts for cruise missiles and sub missiles and in space (or ground-launched, whatever) for ballistic missiles. And let's say that Bush passes the technology around like he said he would or (more likely) it gets leaked by some DoD folks who get astonishingly rich and move to Morocco. Nukes have become passe- fighting, if it is to be done, is to be done by manned weaponry because missiles simply don't work anymore. There might be in-theatre weapons, but you have to get there first, and Metal Gear style gun-fired nukes are not an issue. (As an aside, if something like Metal Gear Ray ever was created...)
This would not, of course, be a recipe for peace. It would be a recipe for war. A lot of war, actually, because all of a sudden all those fabulous military toys that are still pretty much obsolete thanks to the threat of nukes when reasonably big two powers go toe-to-toe become usable again. All of a sudden the world becomes a much more dangerous place, because the apocalyptic threat that serves as a check to ambition disappears and wars for conquest, for vengeance, or simply because a quasi-fascist government is really bored and wants something to do become perfectly acceptable. Money starts pouring into military R&D again, because all of a sudden those nukes that provided the last line of defense don't mean squat any more, and the only thing between, say, Russia and conquest is the strength of their force of arms.
Europe would suddenly become a much more dangerous place to live, and Asia even more so. Even the United States wouldn't necessarily be invulnerable, although it would be a world where the United States could act as a spoiler in any conflict you'd care to name; unless the world actually did become bipolar and the United States was placed up against a foe that could conceivably defeat it. I mean really defeat it: as I said, without nukes, the only thing between the United States and its enemies is the traditional tools of air, sea, and land- tools that aren't nearly as reliable a deterrent as the threat of apocalypse. In turn (and probably because of this) the United States could become a much more belligerent power, because that hanging threat in the back of American minds could turn Bush-style unilateralism into the pacifistic side of the American military discourse. The argument for empire would be a lot stronger, perhaps even unassailable. America's opponents and even allies would know this too.
There would probably be other repercussions too; those are just the ones that are at the top of my head. (What would a world where world conquest is conceivably possible be like?)
Right now, of course, it's very unlikely that Bush's vision of limited NMD would create anything even remotely like that. Still, like in the last entry, it's useful to think long-term, and long-term it's conceivably possible that nukes will by-and-large be relatively unimportant. If it happened to coincide with the growth of an anti-American opposition that I mentioned in the last post...
Well, let me put it this way. The Outback would look very, very tempting. Mate.