Why do insurgent gangs, who have vastly smaller resources and manpower than the American soldiers they fight, continue to try to kill those soldiers? The answer is, because they believe they only have to kill a few more, and the soldiers will leave. They need not inflict a military defeat (which would be impossible, given the strength of the American military)—all they need to do is survive until American voters decide to throw in the towel, which might happen at any moment.
The proper response to that calculation is to make emphatically clear that the fight will not end until one side or the other wins, decisively. That kind of battle can only have one ending, as Abraham Lincoln understood. In a speech delivered a month after his reelection, Lincoln carefully surveyed the North’s resources and manpower and concluded that the nation’s wealth was “unexhausted and, as we believe, inexhaustible.” Southern soldiers be-gan to desert in droves. Through the long, bloody summer and fall of 1864, the South had hung on only because of the belief that the North might tire of the conflict. But Lincoln did not tire. Instead, he doubled the bet—and won the war.
There is another reason economic logic does not readily apply to the fighting of wars. When running a business, one aims to invest just as much as is necessary to make the sale or manufacture the product—no less, and no more. Profit equals revenue minus cost, so minimizing cost lies at the core of wise business management.
Warfare could not be more different. Send just enough soldiers and guns and tanks to do the job, and you may soon find you have sent too few. The enemy concludes that if it can raise the marginal cost of the conflict just a bit, if casualties are a little -higher or the expense a tad greater than you imagined, you’ll quit the field. On the other hand, send vastly more soldiers and materiel than required to the battlefield, and the enemy soon decides that the fight is hopeless—that, as Lincoln so elegantly put it, our resources are unexhausted and, as we believe, inexhaustible.
The difficulties the Army has experienced in Iraq are due, in large measure, to the fact that the Defense Department forgot this historical lesson. Donald Rumsfeld tried to run a businesslike war. But warfare is not business; it is not fought at the margin. By striving to do just enough to win, we have done too little. The right strategy is to do too much.
That is especially true of a war like the one in Iraq. Consider these data: Between November 2004 and February 2005, according to the Brookings Institution’s Iraq Index, the number of coalition soldiers in Iraq rose by 18,000. In that time, the number of Iraqi civilians killed fell by two-thirds, and the number of American troops wounded fell by three-fourths. The soldiers were soon pulled out; by the summer of 2005, American and Iraqi casualties rose again. Later that year, the same thing happened again. Between September and November of 2005, another 23,000 soldiers were deployed in Iraq; once again, both Iraqi and American casualties fell. In the early months of 2006, the number of soldiers fell again, and casualties spiraled up.