Part of the series "Ten Lessons Since the 9/11 Attacks," in which CFR fellows identify the top threats and responses going forward. Read more in the series.
There is no question that the U.S. homeland is now significantly safer from a terrorist attack than it was ten years ago. Of course, the U.S. counterterrorism and homeland security enterprise has many weaknesses; and there remain vast vulnerabilities, some of which present catastrophic "tail risks"--an event that, while very improbable, would cause enormous damage. But different reforms across government--action against terrorists abroad, better intelligence, tighter border security, enhanced law enforcement, and better response capabilities--have greatly reduced the terrorist threat Americans face.
The killing of Osama bin Laden is certainly a psychological relief. Its operational significance remains to be seen, however, and will depend on whether the intelligence gained from the raid will allow the United States to complete the decimation of al-Qaeda.
Meanwhile, something of a consensus has emerged around what the elements of the U.S. counterterrorism and homeland security enterprise ought to be. President Obama has strikingly different rhetoric than his predecessor, but his counterterrorism and homeland security policies are essentially identical; differences have usually been in the direction of sharpening the tactics or escalating the engagements of the Bush administration.
The past decade offers many lessons for the relatively new field of "homeland security." Here are four:
1. Offense matters more than defense. Finding and destroying terrorist cells before they strike is a far better investment than protecting potential targets, preparing to respond to attacks that slip through, or building "resilience."
2. Decisions about how to deal with individual terrorists should be made on a case-by-case, pragmatic basis. This is not an appropriate domain for ideology or trite slogans. The U.S. criminal justice system is not a perfect venue for dealing with international terrorists, but it does offer many advantages over the alternatives and should be employed when and as appropriate.
3. Homeland security is a "one-way ratchet." It is relatively easy for governments to decide to increase security, particularly in response to specific threat intelligence. It is much harder for them to decrease it. This is largely because the incentive structure in homeland security imposes concentrated costs on officials who permit a known vulnerability to persist; but only diffuse costs on those who must bear the burden of the countermeasures. We experience this diffuse cost every time we pass through a TSA checkpoint at an airport. The 9/11 attacks led to the institutionalization of homeland security in the U.S. government, so Americans should expect the government to err on the side of too much security--and too much inconvenience--whenever faced with specific threats.
4. Terrorism is a manageable risk. Politically, of course, it is impossible for anyone in a position of responsibility to articulate a concept of "acceptable losses" to terrorism. But even so, we would do well to note that there are many other national and international challenges that will hurt far more people, with far more certainty, than terrorism ever will. Terrorism deserves a sustained, serious, professional response; it does not deserve to be the centerpiece of U.S. foreign policy.