Yet those who support intervention on moral grounds are often quick to hail their own virtue. John Stuart Mill thought so highly of the British nobility of purpose that he said such unselfishness was "a novelty in the world; so much so … that many are unable to believe it when they see it." In sending French forces to Syria, Napoleon III issued an open letter denouncing the "pitiful jealousies and unfounded distrust of those who suggested that any interests except those of humanity had induced him to send troops to Syria." In fact, countries that intervene militarily rarely do so out of pure altruism. The French deployed forces to Syria partly because of disgust over the massacres of Maronites, but also because doing so might solidify Napoleon III's influence in the region and win over Catholic voters at home. The Russians intervened in the Ottoman Empire in the hopes of gaining control of water ports. Bass quotes from All the King's Men when Willie Stark lectures pure Adam Stanton on doing good: "You got to make it, Doc. If you want it. And you got to make it out of badness. Badness. … And you know why? Because there isn't anything else to make it out of."
But how sustainable is this in the 21st century? The Bush administration is hardly convincing when it endorses water-boarding one day and calls for peacekeepers to be sent to halt genocide the next. This century's debates over humanitarian intervention occur in a globalized world where a country's policies in one place are visible elsewhere, and in a polarized world where a country's lack of credibility or legitimacy undermines its ability to draw allies to its side. Understanding the 19th-century cases, Bass writes, "should contribute to a more humble, sober version of the practice in the future."
Historically informed caution certainly seems the right antidote to Bush-era recklessness. An ethnic, national, or religious group must be in immediate danger of being massacred on a large scale; a credible multilateral body must support the intervention. The countries intervening must forswear up front the pursuit of commercial or strategic interests in the region. They must commit to remaining for a finite period and in numbers befitting their limited mandates (though, as Bass notes, it's important to be careful not to allow the killers to wait out the intervention and to deploy a force sizable enough to protect civilians). Finally, the countries entering a foreign land must have done so on the basis of the good-faith calculation that the benefits of such action would outweigh the costs—to the victims, the region, and the intervening parties.
While instituting such requirements should reduce the risks of cynical or counterproductive interventions, the conditions are in fact so stringent that it is not obvious how or when, in today's world, such conditions might be met. Countries are hardly rushing to contribute troops to the U.N. peacekeeping mission in Darfur. And since China and Russia frown on external interferences that aren't of their own making, multilateral consensus is likely to be elusive. On this score, Henry Kissinger seems increasingly correct that "a doctrine of common intervention can furnish a more useful tool to frustrate action than the doctrine of non-interference."
History is laden with belligerent leaders using humanitarian rhetoric to mask geopolitical aims. History also shows how often ill-informed moralism has led to foreign entanglements that do more harm than good. But history shows the costs, too—in Rwanda and today in Darfur—of failing to prevent mass murder. The fate of future atrocity victims may turn on whether it is possible to find a path between blinding zeal and paralyzing perfectionism.