Since 9/11, however, the theory of pre-emption has been complicated by unequal development among the varieties of American power. The American military has demonstrated an unprecedented ability to decapitate a hostile regime. As President Bush put it following the fall of Baghdad, "For a hundred years of war, culminating in the nuclear age, military technology was designed and deployed to inflict casualties on an ever-growing scale. In defeating Nazi Germany and Imperial Japan, Allied forces destroyed entire cities, while enemy leaders who started the conflict were safe until the final days. Military power was used to end a regime by breaking a nation. Today, we have the greater power to free a nation by breaking a dangerous and aggressive regime."
But it has proved much more difficult to reconstruct -- or construct for the first time -- a working society once a regime has fallen. The Army and Marines have adjusted quickly to the tasks of a counterinsurgency campaign. Development assistance has increased. Yet Americans are better at humbling tyrants than at building nations. In Afghanistan there was no good alternative. But that continuing exertion has made alternatives essential in other places.
So America is left with a strategic challenge: It must pre-empt violence that takes root in failed and outlaw states without occupying and restructuring those societies. The alternative to Afghan-style nation-building is not forgetfulness and passivity. It is the development of alternative forms of American power -- working through proxies, striking with drones, promoting development, conducting covert operations. And sometimes this will mean, as President Obama has admirably demonstrated, the unilateral use of force against America's enemies.
A decade removed from 9/11, America is a sobered power but not a retreating one. Its determination reaches across administrations and to the farthest parts of the world. This continuity of American purpose is the reason bin Laden hid and the reason he died. And we can hope that, in the end, he felt the fear he loved to cause.