Ballistic Missile Defense(BMD) is one of those military assets that — along with the F—22 Raptor, carrier battle groups, and guided—missile subs — have been criticized in recent years as being irrelevant to the new strategic realities of the War on Terror. It's a little difficult to follow the logic here: are there people who really believe that terrorism is the only form of warfare allowed in the 21st century? But after Kim Jong—il's little missile spree, we can be fairly certain we won't hear that one again soon. On the contrary. What the missile incident demonstrates is how important BMD is to any serious terror strategy. 

First, we need to broaden our understanding of the actual role nuclear weapons play in strategy. Deterrence, in which possession of such weapons acts as a restraint on both sides, is widely understood. But there's another related factor also at work: nuclear weapons as a variant of the 'fleet in being.'

Like the huge battleship fleets of the early 20th century that were too valuable to be risked in actual combat, nuclear weapons are useful only when they aren't used. Always offstage, their baleful influence apparent even when not present, nukes extend their power of restraint well beyond the nuclear arena, drawing a line that an opponent's response dare not violate. A nation that cannot carry out a nuclear strike for fear of retaliation is also barred from ordering an invasion, establishing a blockade, or instigating the assassination of enemy leaders.

At the same time, activities below those blatant levels are actually encouraged. Nuclear weapons form an umbrella beneath which proxy wars, espionage, and terrorism can readily occur without being directly challenged, so as not to waken the nuclear genie. During the Cold War, the Soviets took advantage of this effect to the hilt, funding proxy wars and subversion in Africa, Asia, and Latin America, triggering crises in Berlin, Cuba, and the Middle East, secure in the knowledge that the U.S. would not go to the mattresses for fear of triggering an open nuclear confrontation. Under those circumstances, if the U.S. wanted to play at all, it had to be on Russia's terms, so the country became involved in a number of operations in areas we probably wouldn't have bothered with otherwise. Simply put, nuclear weapons enable an opponent to raise the nuisance level to the unbearable and beyond without fear of retribution.

Which is why people like Kim and the Iranian mullahs want them. Not to fight a war with, or to give to terrorists to set off wherever they please (which is a pretty strange idea, if you think about it), but to act as a protective umbrella for other machinations, the same as they did for the USSR. With nukes and a suitable delivery system (it's interesting how often people overlook that last part), the mullahs will be free to reconstitute Hezbollah, take over Lebanon, move into Iraq in force, and anything else that occurs to them. Kim no doubt has an entire laundry list of plans for East Asia, beginning with South Korea, which if he's wise (I'm aware that's asking a lot) he won't occupy but will instead Finlandize and use as a resource.

With nukes as part of equation, who's going to interfere? Europe? The Security Council? The G—8?

And that's where BMD comes in. Properly utilized, BMD can create leaks in the enemy's umbrella. The purpose of a missile defense system is not to stop an ICBM attack dead, destroying every last missile and warhead. This is very likely outside of the realm of possibility, a fact that BMD opponents regularly used in their arguments, claiming that if even one warhead got through, it would be too many. (One of those statements of which it's hard to fault the strict logic, while at the same time being aware it's complete nonsense.)

BMD systems were actually intended to inject a note of uncertainty into calculations involving a nuclear strike. Under the circumstances of nuclear war, there are targets that must be destroyed to prevent a counterstrike — enemy missile silos, submarine pens, bomber bases. With a BMD system in place, could you be absolutely certain to hit these targets? If you couldn't, you didn't attack. And with the expense involved in maintaining and replacing an ICBM force, eventually you'd give up on them completely and move on to something else. (At least that was the hope.)

The point of BMD is to render a sure thing doubtful. Nuclear weapons no longer give carte blanche to their possessors. They no longer provide an unleakable umbrella.

This effect is not theoretical, but a matter of record. By the mid—1980s, the only chips the Soviets had left were a huge tank army and 40,000 nuclear warheads. In his epochal 'Star Wars' speech of March 23, 1983, Ronald Reagan proposed to negate the nuclear chip with a comprehensive BMD system, the Strategic Defense Initiative. The Soviets, from the Politburo and the KGB on down, pulled out all stops in order to prevent such a system from becoming a reality, to no avail. Reagan would not give up SDI for anything — which he proved by walking out on Gorbachev at Reykjavik. And suddenly, proxy wars and subversion lost their attraction. The USSR began behaving itself — and a few years later, it was one with the Habsburgs and Ottomans.

There's no reason this can't work with Iran and Korea. Granted, they're crazier, and will require a more concrete demonstration than the Soviets needed, but this can be arranged.

The BMD effect works more impressively as you go down the numerical curve. An enemy possessing a thousand nuclear—capable missiles, each with MIRV capability, may be uncertain how many of his 5,000 to 8,000 warheads will get through, but he can sure enough will to do mortal damage, if not to what specific targets. How much more so an enemy with a couple dozen obsolete missiles based on fifty—year—old technology and operating at the very edge of their capabilities?

(It's often overlooked that both the Taepo—dong—2 and the Shahab have extremely limited payloads, on the order of 2,000 lbs. It's extremely unlikely that the PDRK or Iran will be able to produce warheads that small for many years to come, and even if they do, it would require a drastic cut in missile range. Alaska and the West Coast should be safe from the Taepo—dong—2 for quite some time.)

American BMD systems are in their early days. The SM — 3 Standard that comprises the heart of the Aegis system and the GMD system are in the process of deployment. Testing has been remarkably successful for missiles under development, with the SM—3 hitting seven out of eight targets and the GMD interceptors five out of ten (for purposes of comparison, the AIM—9 Sidewinder, the most successful guided missile ever built, suffered 13 failures in its first 13 tests). As deployment continues, reliability will improve, and capabilities will expand. The current lineup will soon be augmented by the THAAD (Terminal High Altitude Area Defense) system, featuring a mobile missile that can dispatched toward threatened targets. THAAD has recently completed a series of successful tests. Beyond that are laser systems, and eventually orbital—based interceptors of the type originally envisioned for SDI.

The North Koreans and Iranians, if their outlaw  governments still exist, will likely be still fooling with V—2 derivations. If this can be called an 'arms race,' it will be technical in nature, and one the that U.S. and its partners cannot lose.

One thing remains necessary: a demonstration. The Cold War taught us a lot about the power of impressions in the international arena. The USSR didn't set off larger and larger thermonuclear weapons because there was any target that justified them, but because whoever set off the biggest bombs had the most juju. A country willing to explode a 50—megaton bomb, even in the guise of a test, was a country treated differently from others. We can be sure the lesson has not been lost on Kim.

So we need a new kind of lesson. Namely, the interception and destruction of an ICBM during a test flight. This can be accomplished using not the GMD system based in Alaska, which may still have bugs and ought to be saved for a crisis, but the Aegis system, which is operational and ready for use. Recent comments suggesting that the Aegis system is not suitable for an ICBM interception are less than completely accurate. A terminal—phase intercept may be beyond the Standard's capabilities. But an ICBM on liftoff is, as anyone who has seen a space launch is aware, moving at a crawl for the first moments of flight. They are utterly vulnerable and can be destroyed with ease. The North Korean launch site is on the coast. At least three Aegis—class warships are patrolling the area.

Opportunity awaits.

Nothing would embarrass these people more than to have their latest weapons, on which they've invested so much time and effort, revealed as impotent. The Strategic Defense Initiative, by strength of concept alone, dealt a crippling blow to the USSR. It can work again against this millennium's dictators. If there has to be a new Cold War, then let it be run by our rules.

J.R. Dunn is a frequent contributor.