IN ONE SMALL scene in Charlie Chaplin's classic film "The Great Dictator" (1940), an inventor who says he has perfected a bullet-proof vest asks Hitler (Charlie, of course) to shoot him in the chest with a revolver. When he does so, the inventor collapses to the floor, and Charlie turns away with the wonderfully understated judgment, "Far from perfect."
The imperfect vest is one sort of failed defense; France's Maginot line was another. This string of fortifications built after World War I to block another German attempt at invasion might well have worked had the Germans, in 1940, attacked it head-on as so often happened in the first war. This time, however, the Germans simply went around it, turned the French flanks and carried the day with their infamous blitzkrieg.
We may be forgiven if both of these examples jump to mind when we consider President George W. Bush's missile defense shield proposal - child of President Bill Clinton's initiative, and grandchild of President Ronald Reagan's "star wars" fiasco. We don't know exactly how or whether the shield will work, how much it will cost, whom it will protect us from or when it will be ready. Tests thus far, meticulously crafted to succeed, have mostly failed, so its future (except for the congressional funding) is mostly speculative. At the very moment when the Bush administration is declaring that alternative energy sources such as solar and wind are too technologically dicey to risk significant investment in their research and development, it is pushing a baroque technological system of high-tech components that is truly pie in the sky.
It is wonderfully ironic that Bush's anti-missile system should be called a "shield." We can dispense with the niceties that a "shield" is somewhat larger than a buckler yet smaller than a pavis, according to the Oxford English Dictionary. For our purposes, it is important only to remember that brave fighting men with shields long ago discovered that new technologies of warfare had rendered their defenses useless.
The fact is that we have been here before - not just 20 years ago with Ronald Reagan but 600 years ago when the flowering of medieval life was wilting under the blaze of then-new technologies. In 1495, a fortress in Italy, which had not long before withstood a siege of more than seven years, was reduced to rubble in eight hours by the cannon of Charles VIII. The introduction of firearms into European warfare rendered most defensive technologies obsolete.
The introduction of the stirrup to Europe (we don't know from where and exactly when) had ushered in the age of mounted shock combat. For the first time, soldiers on horseback could administer, and absorb, violent blows such as those delivered by lance, broadsword and battle-axe. The defensive technologies of armor were soon developed to cope with this new offense: Both men and horses were heavily, sometimes elegantly and always expensively outfitted with iron plates and chain mail. It has even been suggested that this innovation in warfare led directly to the creation of a warrior class in European society that paid for its hardware by heavily taxing the peasants in exchange for protecting them in times of danger.
Not only the imposing castles and fortresses but also the armored knights fell to the new improved warfare that relied upon guns. As late as World War I, some British officers were said to cling to the belief that bullets couldn't stop horses, but many an early modern knight learned the hard way that bullets could stop both horses and their heavily armored riders. That historical moment was famously captured by Mark Twain in his darkly comic novel, "A Connecticut Yankee in King Arthur's Court." Sir Boss, the 19th-century American foreman from the Colt pistol factory in Hartford, Conn., tried to reform but succeeded only in destroying the Arthurian England into which he had been projected. Forced to joust with one of the flowers of English knighthood, he quite sensibly - and, for the audience, surprisingly - simply pulled a revolver and shot his rival through both armor and chest. Hardly chivalrous, but, in the nature of the new industrial technology of the 1800s, very efficient.
In the industrial era, such shifts in the fortunes of both offensive and defensive weapons have been common. The combination of elaborate trenches and machine guns in World War I gave such advantages to the defense that brave but hopeless infantry charges across no man's land typically gained only a few yards at the cost of casualties in the hundreds or thousands. When the British introduced the armored tank, however, both trench and machine gun proved less than adequate to protect established lines.
On the high seas, the wrapping of wooden ships in iron sheets to deflect cannon balls led to the all-steel naval fleets of the late 19th and 20th centuries. The tremendous offensive power of these ships then threatened to penetrate even the thickest armor plating, and aircraft carriers were invented to provide an aerial umbrella of protection over them. The enemy's aircraft, of course, as we learned in the Pacific early in World War II, were equally destructive to our ships. We continue to build large naval vessels, but perhaps more to keep shipyards working than for any real defense purpose. We haven't had many chances to see how all our new weapons work in actual practice over the years since World War II, but in 1982 a French Exocet missile (cost: $200,000), fired by an Argentine fighter, sank a $40,000,000 British destroyer in the Falkland Islands war.
As these historical examples suggest, there is always a race between offense and defense in the military, and one or the other always tends to be in the ascendance. This does not even take into consideration that the difference between offense and defense is not always obvious. The handgun on your bed stand, for example, can be used to shoot the burglar or your spouse. No offensive weapon long remains overwhelming, and no defense forever certain.
Herbert York, the nuclear weapons expert turned arms control advocate, long ago noted that during the Cold War, the United States was essentially in an arms race with itself - the Soviet Union could just as well have disappeared (as it has!), and we would keep on racing. The reason, York pointed out, is that as soon as our scientists and engineers develop a wonderful new offensive weapon, we assume that the enemy will immediately try to find some defense against it. We must hurry to do so first, of course, in order to tweak the new system to take their hypothetical defense into account before the enemy can actually put it in place. The same works for defensive systems. When we have built a new one, we must try to think ahead of the enemy and anticipate the ways in which he will try to penetrate it. It's an endless race, and one that doesn't really need an opponent; all it needs is more appropriations.
If Bush's shield is indeed intended to guard against missile attacks from "rogue" states, it is likely to fail more like the Maginot line than Chaplin's bullet-proof vest. "Weapons of mass destruction," as we like to call them, can be delivered to America through any number of means. Biological, chemical and even nuclear weapons can be smuggled in over our borders by land, sea or air. Our lack of success in that other war, on drugs, suggests that interdiction is not to be counted on to keep out that which we wish not to enter the country.
In 1890, the Indians of the Great Plains were desperate for escape from the relentless and ruthless encroachment of white American settlement on their lands. Beginning with the Paiutes of Nevada, they turned to the Ghost Dance, a quasi-religious movement that promised the elimination of the white invaders and the restoration of Indian traditions and tranquility.
It was a peaceful movement, though the Sioux in South Dakota created a dangerous variation: the Ghost Shirt which, when worn by Indian warriors, would shield them from the bullets of army guns.
At Wounded Knee in 1890, the Sioux, relying upon the shield of their shirts, engaged U.S. troops and were cut down by superior numbers and the firepower of machine guns. The Indians lost at least 150 dead, including women and children. Their Ghost Shirts had failed the only test that counted - that of actual war. Ours are likely to as well.
Carroll Pursell is the chairman of the department of history at Case Western Reserve University and an Adeline Barry Davee Distinguished Professor.