This week marks the first anniversary of the killing of Osama bin Laden. What should be a cause for nationalistic chest-beating by all Americans has become, like everything else these days, a source of partisan rancor instead. But, to me, the most striking thing about the anniversary is not the hothouse political combat it is engendering, but instead the degree to which it underscores a perennial and pernicious feature of the American psyche: our tendency to lurch from one extreme to another.

We see this tendency in economic policy, with one extreme arguing for virtually no government intervention whatsoever in the marketplace (except, of course, where its own parochial interests require it) and another arguing for a government solution to virtually every problem. Common sense, as well as bitter experience, calls for a balance between the two. Left entirely to their own devices, some in the private sector will defraud consumers and abuse workers. And, left entirely to their own devices, some in government will make bad business decisions and unduly restrict individual freedom.

The same is true of terrorism. In the years following 9/11, the nation has lurched from one extreme to the other. Just after the attacks, there was hysteria. As the years have gone by without, thankfully, another major attack, the nation is in danger of slipping back into pre-9/11 complacency.

Yes, it is true that terrorism appears no longer to pose a strategic threat to our security. It is not only bin Laden who is dead, but also his perhaps even more charismatic and dangerous young American-born acolyte, Anwar al-Awlaki (the operational force behind Al Qaeda's Yemeni franchise, al Qaeda in the Arabian Peninsula, or AQAP), and scores of lower-level figures. Al Qaeda Core, the organization that bin Laden created and that his longtime No. 2, Ayman Al-Zawahiri, now heads, appears now to be a spent force. Its regional franchises, most notably the one in Yemen, continue to be a cause for concern, but policymakers believe that, excepting AQAP, they can be contained within their regional boxes for now.

Lone wolves can kill people here and there, but, almost by definition, they cannot carry out the kind of game-changing attack that was 9/11.

And, meantime, there are serious threats to national security that demand our immediate attention. Among them is China's inevitable rise as a military power; instability in North Korea; the prospect of war with Iran over its nuclear program; and the possibility of being dragged somehow into the civil war in Syria. Our continued economic fragility and our huge and growing budget crisis threaten our ability to use military force when necessary, limiting our diplomatic maneuvering room around the world.

And, yet, none of this means, or should mean, that America can go back to sleep as far as terrorism is concerned. There is the danger of just that if commentators' comments on this anniversary are read to suggest that we are out of the woods now. I worry about the words of one of our most esteemed (and rightly so) terrorism experts on the eve of this anniversary, Peter Bergen, who said the other day, "Seventeen Americans have been killed by al Qaeda or people influenced by its ideas since 9/11. More Americas die in their bathtubs by significant amounts, by accidental drowning. We don't have a fear of accidental drowning."

Indeed, we don't have a fear of accidental drowning, while we do have a fear of terrorism. And the reason for that is that they're totally different things!

It is not the number of people who are killed by terrorists that inspires fear, though, of course, the greater the number, the greater the fear. It is the very fact that people are being killed, or are at serious risk of being killed, by unknown individuals for political reasons over which victims, or potential victims, have absolutely no control. The psychic impact of terrorism; the political impact of terrorism; the economic impact of terrorism are outsized relative to the number of people killed because of the unique nature of terrorism. It is the randomness of it; the politicization of it; and the deliberate targeting of civilians that make terrorism a thing apart.

Given the infinite number of targets; the open nature of American society; the vulnerabilities that remain in our counterterrorism defenses (with due credit for the significant security advances that have been made in the last decade); terrorists' determination to carry out more attacks (a determination that is no doubt heightened by their lack of success in recent years); and the ease with which, at least, low-scale attacks can be carried out, the odds remain in terrorists' favor.

What we need, then, as everyone agrees, is "perspective." But, putting terrorism in perspective shouldn't mean all but forgetting about it if few -- or, for that matter, no -- people are killed. It should mean doing everything within our power to reduce our vulnerability to terrorism and to limit terrorists' ability to attack again, while recognizing that we can never be 100% safe and that, one day, terrorists will strike again.