Geez, I see the impossibility of the BMD system, and I'm probably one of the biggest hawks on this board.
Realistically there are 4 main nuclear threats.
1) Ballistic missiles - The big one carries the biggest payload, for example the SS-19 carries of to 6 Mirvs with a yield of 750 kilotons to 5 megaton city busting warheads. The best way to deal with these is to bust thier bunkers before they can launch, however for example, the Russians and the middle eastern nations have put a great deal of money and research into developing a mobile launch system which reduces the effectiveness of a pre-emptive strike. The missile defense shield is probably the best way to deal with this since a first strike without conditions is a international no-no. The problem is that these warheads decend at a tremendous rate, you don't have a lot of time to shoot them down, and atmospheric(sp?) and rolling might prevent a good shooting solution. A single warhead simple missile could be taken out, but a mirv'd system with multiple decoys and more then one missile might be impossible. Besides the BMD is not designed along the same line as star wars which is knocking down hundreds of missiles, its designed to counter a unsophisticated attack by early generation technology (single missile, single warhead)
2) FOBS - Orbital bombardment by using a warheads that orbit 150 km's up. No nation legally uses these thanks to SALT II, however there is no warning time with these weapons.
3) Submarine launched Nuclear Warheads. By creeping up onto the continental shelf of a nation and launching a depressed trajectory shot there is literally one minute of warning before the target is hit. The BMD is useless against this because of lack of warning and the fact that a cruise missile basically flys between buildings. a phalax missile defense system could probably deal with this, but the patriots performance was terrible against it in tests.
smuggled devices/improvised devices - There is no defense against this due to the massive influx of containers, luggage, mail into the continental U.S., the task of detecting this is next to impossible and economically undoable, this is the likely way that any kind of terrorist is going to nuke the U.S.
The BMD shield is suppossed to be one part of the U.S. homeland securities holy trinity, knock down a simple missile attack by a rogue nation, improve intelligence to snuff out the attack before it can be born. Secure the ports and borders to prevent a device from being smuggled in. Currently the U.S. has badly failed on all three.
Lanny, on another note, I've noticed that you tend to argue based on absolutes (Are you sure your not a Sith Lord
) Your arguement on the U.S. use of the nuclear warhead is a bit extreme. The correct understanding on the situation lies somewhere between the point that you are making and the point that others are making.
The Japanese had sent out feelers about a negotiated settlement, however thier demands were unreasonable and represented a position that the allies could not agree on.
The allies were prepared to go as far as invading the home islands of Japan as intelligence at that point indicated that the Japanese military was content with fighting down to the last man, woman and child.
Would the firebombing had ended this, not really, did the firebombings in Germany and the destruction of thier industrial centers end resistance in Germany, and force the surrender of the third reich, they actually had to continue to slog into Germany as the Russians did even though there was no reason for the Germans to keep fighting.
The first Nuclear bomb was neccessary to force reality onto the mililtary leaders in Japan and more importantly shock the Emporer into facing the reality of the situation. The second bomb was more of a warning against Stalin himself that the American's were capable of building multiple bombs and deploying them. You also have to realize that the Japanese were given a warning about the use of the second bomb well in advance of its use demanding the unconditional surrender of the Japanese people, but they chose to gamble that the American's didn't have a functional second bomb or would not use it. A long war changes the decision making process, this was the ultimate corner cutter to end the war and save American lives because a invasion against a fanatical military on thier home field would have been a meat grinder for soliders and civilians alike.