It is said that during the 1973 Yom Kippur War—known on the other side as the Ramadan War—an Israeli military spokesman was asked for the fourth or fifth time whether the Jewish state would use nuclear weapons if its ground forces continued to suffer defeat. He repeated the official mantra—"Israel will not be the first country to deploy nuclear weapons in this region"—and then stepped back from the microphone (which he believed to have been switched off) and whispered to himself, "And we won't be the second one, either."
Warfare is an enterprise where, very noticeably, nice guys finish last. Franklin Roosevelt famously and pugnaciously said, after the "day that will live in infamy" in 1941, that it would count in the end not who fired the first shot but who fired the last shot. Nonetheless, it hurts to begin a war with the loss of a fleet, and not all countries are big enough to sustain such a shock. As a result, military historians and military strategists spend a good deal of time arguing over "pre-emptive" war and its near cousin "preventive" war.
Most of this discussion is impossibly abstract and subject to the rule of blind contingency. The only certain way of preventing World War II, for example, would have been for the Germans to have won World War I. (This outcome would also have forestalled the rise of Nazism.) But the British and French military planners of 1918, with their American allies, could obviously not be induced to see things that way. The other, rather belated, way of preventing World War II from becoming a world war would have been a united front between Britain, Russia, and France to crush the Hitler-Mussolini forces before they could get properly started. It's not as if there would have been a shortage of pretexts. But then many Germans to this day would be insisting that their country had been a victim of aggression, and the political consequences of that might have been nasty as well.
The United Nations Charter reserves to all member states the right to use unilateral force if they can invoke the clause that specifies "self-defense." But this means by definition that an aggressor must have shown his hand and initiated a war before any compensating or retaliatory action can be taken. Some nations don't care to be branded as "aggressors" and will go to some trouble to avoid the charge, but in general it's a bit like the old "no spitting" signs that I used to see on British buses. Who, likely to expectorate on public transport, will be deterred from doing so by a notice? These injunctions apply only to those who would obey them without being told.
Take the extremely flammable situation along the Indo-Pakistan frontier. Pakistan is much smaller than India and has a much smaller army. It also has a "waist," geographically speaking, which means that a sudden Indian "conventional" strike could punch across the border, cut Pakistan in half, and separate its capital city, Islamabad, from its only seaport in Karachi. It is this strategic nightmare that determined the Pakistanis on the acquisition of a nuclear capacity, with which they could destroy Indian armor and infantry as it was massing. Which side would then be the aggressor? The one that was massing, or the one that vaporized the potential assault force? In the early Clinton years, the Pakistanis became sure that they were about to be attacked and prepared to launch, and the American officials who stopped the clock with only minutes to go are still inclined to shiver as they recall the moment. Gen. Pervez Musharraf has since boasted publicly that if India had taken one extra step over the Kashmir question in late 2001, he would have ordered a pre-emptive nuclear attack. But this demented logic holds for all nuclear powers, all of whom are aware that the only real use for such devices is in an overwhelming first strike.
Israel's classic pre-emptive war in June 1967, which destroyed the Arab air forces on the ground, was also justified as preventive because it stopped an attack before it could get started. But the Nasser side could and did reply that in 1956 Israel had attacked without any such provocation, so this was just their slow-motion retaliation for an original first strike. Winston Churchill spent much of his career hoping to entice Germans or Japanese into attacking American ships, the better to lure them into war with the United States and then get the United States to declare for Britain. This was pre-emption of a high order, by means of proxies who unwittingly did what was wanted of them and widened the war in order to shorten it.
In the present case of Iraq, a pre-emptive war is justified by its advocates on the grounds of past Iraqi aggressions and the logical presumption of future ones—which would make it partly retaliatory and partly preventive. This is fraught with the danger of casuistry since if no sinister weaponry is found before the war begins, then the war is re-justified on the grounds that it prevented such weapons from being developed. (And if the weapons are found, as one suspects they will be, after the intervention has taken place, then they could be retrospectively justified as needful for defense against an attack that was obviously coming.)
Surveying the bloody past, one can only wish for the opportunity to rerun the tape so that enough judicious force could have been employed, in good enough time, to forestall greater bloodshed. Everyone will have their favorite example. If only, for instance, the U.N. troops in Rwanda had been beefed up and authorized to employ deadly force as a deterrent. But tautology lurks at every corner, and the distinction between "pre-emptive" and "preventive" becomes a distinction without a difference, and only hindsight really works (and not always even then). The lesson is that all potential combatants, at all times, will invariably decide that violence and first use are justified in their own case.