Since I wrote a paper on Star Wars/SDI/Missile Defense/etc. back in the late 1980s, it has been my belief that President Reagan merely restarted in 1983 what had been shut down by the 1972 Anti-Ballistic Missile Treaty. Essentially, the defense contractors who had been working on ABM technology in 1972 continued to work "on spec" until what was roughly the same program was started up again in 1983. So when we speak of Missile Defense, we're really talking about a program that began during the Eisenhower Administration, i.e., about a 50+ year-old program.
Would the program ever have produce worthwhile results? I think so. During the October 1986 Reykjavík, Iceland Summit, Reagan and the General Secretary of the CPSU, Mikhail Gorbachev appeared about to make a deal to eliminate nuclear weapons entirely. The sticking point apparently, was that the US had to surrender Missile Defense. Unfortunately, as with G.W. Bush in 2003 with Iran, Reagan proved unable to recognize when the deal was as good as it was ever going to get and to cash in his chips while the cashing in was good.
The Center for Arms Control and Non-Proliferation estimates that the US has spent about $60 billion on this worthless boondoggle since the Bush Administration took office. The program has failed test after test and shows no signs of ever passing those tests within the next few decades. Remember, this is a 50+ year-old program!!!! If there's no apparent success after all this time, we're not just talking about a few wrinkles left to be ironed out, we're talking about major, fundamental flaws. My paper in the late 1980s compared the 1943 bombing of Schweinfurt, Germany with the Missile Defense program of the time. The media was in the habit of speaking of a 99% success rate in being able to shoot missiles down. My example and comparisons showed that a 5% or 10% success rate was far more likely.
Also, the program has produced completely unnecessary tensions with Russia.
It's time to shut this program down. Permanently.
Update: The Weekly Standard composed a plea to our President-Elect to keep "Star Wars" going. I considered that to be a silly thing to do and wrote a lengthy piece in response.