Terrorists are named after an emotion for a reason. They use violence to produce widespread fear for a political purpose. The number of those they kill or injure will always be a small fraction of those they frighten. This creates problems for leaders, and even analysts, when they talk publicly about terrorism. On one hand, leaders need to convince the public that they are on the case in protecting them, or else they won't be leaders for long. On the other hand, good leaders try to minimize unwarranted fear.

One reason is that we shouldn't give terrorists what they want. Another is that fear is a real social harm, particularly when it is exaggerated. Stress from fear harms health. It causes bad decisions. For example, if people avoid flying and drive instead the number of added fatalities on the road will quickly surpass the dead from a typical terrorist attack. Most important, excessive fear causes policy responses that often damage the economy without much added safety. Measured in lives on dollars, reactions to terrorism often cost more than the attack themselves.

If leaders talk only about the danger of terrorism and everything they are doing to fight it, without putting danger in context, they may be on safe political ground, but they risk causing or prolonging groundless fear and encouraging all sorts of harmful overreactions. That is the Bush Administration's counterterrorism record, in a nutshell. If leaders just say "calm down and worry about something more likely to harm you," they will be butchered politically.

So a reasonable approach is to sound concerned but reassuring. You want to convince people that they are mostly safe without appearing complacent. I don't like many of this administration's counterterrorism policies, starting with Afghanistan, but thus far its communication about terrorism is far more sensible than the last administration's. That includes the aftermath of this attempted Christmas Day attack.

The administration made it clear that it is unacceptable that a guy we just got warned about got onto a plane wearing explosives. But the President also said Americans should be generally confident in their safety from terrorism. He didn't act as if this incident was the most important thing on his schedule this year or compare the Al Qaeda affiliate in Yemen to the Third Reich or what have you, exaggerating their capability and power. I wish he had gone further and said that detonating explosives smuggled on to a plane is tricky and that flying remains incredibly safe. (Jim Harper will soon have more to say here on the security failures and how to talk about them.)

In a different political universe, the President could describe the terrorist threat honestly. He would say that recent attempted terrorist attacks in the United States show more amateurism and failure than skill and success. He could add that we are fortunate that our greatest enemy, al Qaeda and its fellow-travelers, are scattered and weak compared the sorts of enemies we historically faced. He would sound more like Michael Bloomberg, who told New Yorkers that they had a better chance of being struck by lightening than killed by terrorists, after a particularly inept terrorist plot on JFK airport was uncovered. He could even quote Nate Silver, who calculates that in the last decade of US flights, there was one terrorist incident per 11,569,297,667 miles flown. It's true, as Kip Viscusi demonstrates, that people don't think like actuaries. They rightly value different sorts of deaths in different ways, and want more protection against terrorism than other dangers. But knowing the odds is still important in weighing the appropriate amount of concern and forming policy preferences. The president could also have treated voters like grown-ups and pointed out that whatever flaws in airline security that this attempted attack reveals, there is no such thing as perfect safety, and sooner or later even the finest security systems fail.

I also disagree with the argument that the trouble with our airline security or national security policy-making in general is insufficient presidential attention. Overall, we could do with a little more masterly inactivity in security policy, to use an old British phrase. Aviation security is another matter, but I struggle to see how presidential involvement would have fixed this problem. The 9-11 Commission did claim that September 11 occurred because leaders failed to pay sufficient attention to al Qaeda, but there, as in other matters, the Commission is wrong. At least in the executive branch, the attention paid to the threat in the 1990s was quite substantial, as you can see in this essay by Josh Rovner or in my contribution to this book. The historical record shows that the threat was well understood by security officials and the reading public. Time, for example, called Osama bin Laden the most wanted man in the world when they interviewed him in 1998. The trouble, in my opinion, was not misperception but our policies and the difficult and unprecedented nature of problem--a terrorist group ensconced in hostile country that refused to do anything about it.

Getting the line between confidence and vigilance right is not easy, but it starts with acknowledgment that there is such a thing as overreaction. That subject will be the on the agenda for our January 13 counterterrorism forum with James Fallows, State Department Counterterrorism Coordinator Daniel Benjamin, Paul Pillar and others.

*My attempts to explain this stuff to Politico yesterday resulted in some confused and inaccurate uses of my quotes in this story by Carol E. Lee, which unconvincingly compares the Obama's response to this terrorist attempt to his silly involvement in the Henry Louis Gates arrest fiasco. First, Lee absurdly uses me as example of "predictable" attacks from the right on Obama, when I said I was glad that the President said Americans should feel confident but that I'd have preferred if he'd done it more forcefully by saying flying remains safe and al Qaeda weak. That is more or less the opposite of the predictable take on the right. Then, she says that my views on the President's response to the attacks referred to his post-press conference golf outing. I was talking about his overall response, or lack thereof, over the last several days. I can't decipher the meaning of presidential golf.