yeah, sure. Beats wasting money on welfare.
Frankly, most of the arguments against ballistic missile defense are shallow, short-sighted, and generally ignorant of the topic.
Against the USSR, which was capable of a total saturation bombing of the United States, SDI made sense. A system doesn't have to be 100$ effective to work as a deterrent. All that's needed is to prevent the enemy from having the assurance that a first strike can completely eliminate our ability to retaliate. Hence, our nuclear missile submarines. SDI was effective because even if it could only stop 50% of the incoming missiles, the enemy couldn't be sure WHICH 50% got through...so New York could get all it's bombs on target, and all of the missile silos in the Midwest might get missed.
Would you try a surprise attack on a man if you couldn't be sure if you could disarm him first? Probably not.
Rogue states. We should have SDI because they're run by nuts, and they might be willing to drop a bomb on Hollywood if they had nothing else to do that day. Our investment in SDI requires the enemy to invest even more in their missile programs. It clearly takes a bigger fraction of their GDP, so our investment is worth it.
Yeah. They might sling a bomb to the keel of a 40 foot sailboat and cruise into San Diego harbor tomorrow, taking out both the submarine base at Ballast Point and the aircraft carriers at North Island, for example.
We couldn't do anything to stop that, it's not related to the issues of ballistic missiles, and, frankly, it's not a strategic method of weapon delivery.
You can't say SDI is irrelevant just because other modes of delivery are possible. It's like saying there's no point in wearing seat belts because sometimes a pedestrian gets killed in a car accident.