You also left out vehicular delivery. Drive it up from Mexico.

Don't get me wrong. I like SDI research. We should continue it. It should be installed on naval warships and other military places.
Good usage.

I'm just worried that people are going to spend billions a defense system that can and will be circumvented.
Yes, we will. And we will be surprised when our defenses fail to protect our cities.

Again, people should read about attack trees from Bruce Schneier.

Our COUNTRY (the land, the cities, the roads, etc) will NOT be attacked via ICBM's.

The ICBM scenario is from the Cold War with Russia.

We will be spending TRILLIONS of dollars to defend against an attack that DOES NOT EXIST ANYMORE.

It would be a better DEFENSE to take some of that money and help Russia.

But then, I've always viewed the situation slightly differently than most people. Remember the Marshall Plan.