Strategic Defense Initiative

Scientists: WTF is this? Reagan: Oooh, shiny!

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Don't worry. We have an article about the other "Star Wars". The one you were probably thinking of.

The Strategic Defense Initiative (SDI), also known as the "Star Wars" program (1984-1993), was the batshit brainchild of the Reagan administration, perhaps based on a movie Reagan himself once saw. The basic plan was to build a defense system against nuclear attack, in violation of arms control treaties signed with the USSR. In the most fanciful versions imagined, this involved "exotic" space-based lasers/rockets destroying missiles soon after launch. While all of this was supposedly deemed possible, the technology that existed 41 years ago when SDI was announced was nowhere near precise enough to pull it off. However, the idea took hold with certain paranoid types who were convinced that the US could not depend on the Soviets acting rationally. Not to mention assorted organizations and people who knew a gravy train when they saw one: some just to stick their noses in the trough, others to get funding for serious research.

The standard conservative retcon is that this clearly unworkable idea: a) contributed to other technological advancements that just couldn't have been done in any other context, or b) was in fact a fantastically clever ruse to get the Soviets to spend more than they could afford on building missiles with Multiple Independent Reentry Vehicle (MIRV) warheads to overwhelm a hypothetical SDI system — and that Reagan therefore caused the collapse of those darn commies personally. Brilliant!

Why it was outlawed to begin with

Many people are surprised to learn that the US and USSR had signed treaties to outlaw these kinds of "shield" programs (they assume that anything "defensive" in nature must be a good thing). However, deterrence theorists realized by the 1960s that the only way to prevent nuclear war was to make sure that no nation would be willing to risk an attack on another nuclear power. This idea was known as "mutually assured destruction" (MAD). If the US attacked the USSR, or vice versa, the US could not be certain to destroy all of the USSR's nuclear missiles and prevent a retaliation strike. Similarly, with so much of the US's nuclear capacity stationed in off-shore submarines, the Soviets could not destroy the American second-strike capability. Therefore, there would be no possible victory scenario in a nuclear war: per the famous line in the movie War Games, "the only winning move is not to play."

To this end, anything that could protect a state which initiated a first strike from retaliation was considered bad. Even a system that was only 10 or 20% effective was risky, because a nation might get arrogant and believe it could knock out 80% of its opponent's second strike, thus not needing a full shield. To this end, a shield against second strikes, even if only partially effective, gravely lowered the effects of nuclear war (for one party) and thus increased the overall risk.

Moreover, a nation confronting a state with such a shield might also be more belligerent, and try to attack first, so that their own nuclear forces would have the best chance at getting through. Such are the intricacies of nuclear deterrence.

The limitation of such systems was discussed at the Strategic Arms Limitation Talks and cemented when NATO and the Soviet Union ratified the SALT I treaty in 1972, which limited anti-ballistic missile (ABM) systems to one each. This was due to the fact that the Soviet Union already had a functional ABM system protecting Moscow using the A-350 (NATO: ABM-1 Galosh) interceptor missile, which sidestepped all the "hitting a bullet with another bullet" accuracy issues of the Reaganite SDI system by using a 2-3 megaton nuclear warhead. The US never managed to get a counterpart system online despite substantial work on the LIM-49 Nike Zeus and later the Sprint missile and Nike-X system, the latter in many ways the ancestor of the SDI concept.

Usefulness

“”$100 billion dollars against an attack mode which is literally the most inconvenient, least likely way for bad guys to kill Yanks. Terrorists don't have missiles. Terrorists have VANS. A white-panel-truck defense shield, THAT would be worth our money. Tie the INS database into the Ryder rental computer. Now we're talking science.

—Kung Fu Monkey

One of the problems with the shield today is that it is no longer clear who exactly it is meant to defend against. The present-day holders of atomic weapons are the USA, UK, France, Russia, China, India, Pakistan and Israel; and previously Apartheid-era South Africa. Given that the ideological differences which once caused the Cold War have largely disappeared, and that they are very dependent on each other for trading purposes, the possibility of a nuclear war between them has been considerably reduced.

That leaves rogue states like North Korea and Iran. North Korea has already detonated nuclear weapons, and the possibility certainly exists that other rogue states could provide nuclear weapons to terrorist groups. Their problem then becomes one of delivery. The superpowers got around this by creating intercontinental ballistic missiles, which enable them to launch massive coordinated attacks on any point of the world. (An ICBM blasts a warhead into space on a sub-orbital ballistic trajectory, hence the name "ballistic" missile.) Until 2019, North Korean missiles had consistently flopped into the ocean mid-trajectory.

Perhaps surprisingly, missile technology is a lot more complicated than nuclear weapons technology, in which the major problem is getting hold of the nuclear material and concealing the large facilities needed to purify it to weapons-grade. It also needs a lot of testing which, given the nature of the activity, can hardly be carried out in secret. In the event that someone launched an attack, it would be very clear where such missiles were launched from.

But why would a state, or terrorist group, bother with this? If you are only going to launch one or a handful or weapons, why would you go to the bother of developing this technology when you could simply put your bomb on a ship and sail into New York Harbor? It would be cheaper, simpler, and more reliable. It would have the added advantage of being anonymous and would possibly allow you to escape the certain overwhelming US retaliation.

Feasibility

The SDI system must never get any system-wide false positives, and would have to work perfectly the first time it was needed. That distant sound you hear is every computer geek on Earth laughing bitterly at the idea.

In testing, the SDI system didn't seem to manage better results than shooting down one in three test missiles, fitted with radio transponders, on a clear day. This should not fill you with hope.

Using principles of electronic warfare, it is possible to overwhelm any missile defense with a threat cloud (i.e. a high-tech smokescreen) deployed by one or more ICBMs. This is a relatively cheap countermeasure consisting of dummy warheads mixed in with the real warheads (referred to as "penetration aids"), as well as radar-reflecting metal chaff and infrared-emitting aerosols, thusly preventing the missile defense system from being able to reliably eliminate the actual threats. The real warheads can in principle be identified by their greater mass as compared to the decoys, but this can only be used to discern warheads as they accelerate or decelerate, meaning the difference in mass can only be detected during the final moments of the warhead's flight as they reenter the atmosphere. The end result would be an overwhelmed computerized system flailing about and wasting all of its counter-missiles on duds, allowing the real warheads to slip through, and then, well, kaboom.

Nuts

Lyndon LaRouche was a big supporter of SDI, and claimed that he came up with the idea and sold Reagan on it back when his associates were trying to infiltrate the Reagan administration. This claim is probably untrue; it is in keeping with LaRouche's tendency to distort public policy initiatives and either try to claim them as his own, or promote weird LaRouchian versions of them. But there was some bit of toying around there as the Reagan administration eventually cut off contact with the LaRouchies after embarrassing media stories made this an issue.

Edward Teller strongly lobbied the Reagan Administration to support SDI despite the scientific consensus that it would not work as claimed.

It should be to no one's surprise that Dick Cheney was picked to heap nostalgia about SDI on its 25th anniversary.

See also

• Game theory
• George C. Marshall Institute
• Nuclear winter
• Dr. Strangelove — a black comedy about nuclear defenses gone awry

External links

• Did Star Wars Help End the Cold War? - The comprehensive demolishment by Pavel Podvig
• Israel's Iron Dome Does Not Vindicate SDI
• Another possible use for SDI - Orbital laser assassinations!