What Good Is Military Force?

An observer of this summer’s party conventions would get the idea that the use of military force is almost always and everywhere wrong and ill-advised. Any reference to the use of force was drowned out at the conventions by chants of "America First" and "no more war." With the exception of Donald Trump's open-ended threat to "knock the hell out of ISIS," there seems to be a political consensus that the use of force is almost never a good idea. On the campaign trail both candidates have reinforced this view, often promoting a false choice between rebuilding America and being the world's policeman.

Is the use of force a defensible foreign policy tool and, if so, when and why? There are two main arguments against the use of force, either in specific instances or as a more general policy. The first is pragmatic. Are the goals of the use of force vital to America's national security? If so, are these goals important enough to justify the likely costs in terms of American lives and treasure? And if they are, can policymakers be relatively confident the use of force will achieve their aims, without unintended and destructive consequences beyond the immediate military objective? These are serious questions, to which we shall return.

The second major argument against the use of force is a moral one. This argument holds that the United States has no legitimate basis to intervene in the affairs of other nations, including nations ruled by tyrants. This argument offers clear-cut operational guidance: It is wrong for the United States to intervene abroad with force. And by implication, nonintervention is the morally sound choice.

Though clear-cut, this latter argument is so simple as to be simple-minded. Was American nonintervention in the Rwandan genocide of 1994 a moral policy? More than 700,000 Rwandans were hacked, burned, or otherwise tortured to death and more than two million others were displaced. If the United States could have prevented most of these deaths at little cost in American lives and dollars, would this not have been a legitimate, moral use of military force? Bill Clinton later said his failure to respond to this genocide was one of his presidency's greatest failings. He said that intervention could not have prevented the violence but could have reduced it substantially. Of his choice not to intervene, he later concluded, "I regret it."

There might have been solid pragmatic reasons to stay out of Rwanda. Occurring only a handful of years after the demise of the Soviet Union, the Rwandan genocide offered an early case in which local instability had no larger geo-political implications. During the Cold War, every instance of violence or instability was seen through a zero-sum lens: If the United States did not intervene, a fertile field was opened up for Soviet expansion. Why, in this new world, should Washington risk even one life or one dollar? Why risk another Somalia-like disaster if there is no American cost to inaction? Though it is hard to find any moral grounds on which to defend President Clinton's inaction, these practical considerations remain a matter of judgment.