So, through the end of the Cold War, deterrence worked only when it came to keeping the nuclear peace; many conventional and irregular wars erupted throughout the world. The idea of waging preventive war faded like another darkening dream, abandoned early on. And the extended flirtation with preemption was ended decisively by Ronald Reagan who asserted that "a nuclear war cannot be won and must never be fought." Reagan instead focused on improving classical defense, in the firm belief that the best path to security lay in rebuilding the conventional U.S. military -- the Special Operations Command arose on his watch, too -- in the wake of its post-Vietnam doldrums.
But all that was then. Since the turn of the millennium and the onset of the long conflict with al Qaeda, the hope has been that deterrence, prevention, and preemption might somehow prove more useful than ever before. With the principal enemy being a network rather than a nation, deterrence now focused on the basic principle of denial rather than punishment. A network has no clear homeland that can be threatened with nuclear or other forms of retaliation, so the focus must be on making it seem so hard to reach a target -- "denying" it to the enemy -- that attackers call off their operations or strike elsewhere. To some extent, American homeland defensive measures have achieved a bit of this kind of deterrence. But this has not deterred terrorism overall, just redirected it. Indeed, there is now so much more extremist violence today than there was a decade ago that it can be truly said that the war on terror has morphed into terror's war on the world. Recent closures of so many American embassies and consulates across a swath of Muslim countries only reinforce this point. Deterrence may be working, but only a little, and in a very limited way.
What of preventive war? Fifty years after Eisenhower rejected it, George W. Bush brought it back in his invasion of Iraq. While the Bush administration called it "preemptive war," this was a misnomer given the absence of any imminent threat. The war was really preventive, the idea being that the overthrow of Saddam Hussein would keep him from developing nuclear weapons and would somehow create a less permissive environment for the future growth and sustenance of terrorist networks. There is little need to detail the costly failure of this preventive campaign, beyond noting that today the U.S. military is out of Iraq, al Qaeda is back, and that tortured land has become a hothouse environment for the growth of violent extremism.
With deterrence on life support, and preventive war fully discredited, preemption is the world's last, best hope for security. While it is a concept that proved poorly suited to strategies for the use of weapons of mass destruction, an era of "mass disruption" caused by small terrorist cells and hacker networks cries out for preemption. A raid on a terrorist training camp or safe house, a cyberstrike on a malicious, hacker-controlled robot network, these are the ways in which preemption can be used to reduce the threats that so imperil our world.
The beauty of the kind of preemptive operations that are possible today lies in the very low material costs of such a strategy. The challenge lies in the need for knowledge -- indeed, increasing knowledge over time -- to enable these sorts of strikes to be conducted. And the fact that preemption can only function on the basis of accurate insight should make the case for governments around the world to continue to amass and employ big data to search out the small cells that bedevil our era. One can only hope that the mass publics of the world will come to see the purpose, and the promise, of the information systems that support the only pillar of international security still standing.