Why have there been no terrorist attacks in the United States since 9/11? It is ridiculously easy for a single person with a bomb-filled backpack, or a single explosives-laden automobile, to launch an attack. So why hasn't it happened? The answer is surely not the Department of Homeland Security, which cannot stop terrorists from entering the country, legally or otherwise. It is surely not the Iraq war, which has stoked the hatred of Muslim extremists around the world and wasted many thousands of lives. Terrorist attacks have been regular events for many years -- usually killing handfuls of people, occasionally more than that.

Is it possible that there is a simple explanation for the peaceful American homefront? Is it possible that there are no al-Qaeda terrorists here? Is it possible that the war on terror has been a radical overreaction to a rare event? Consider: 80,000 Arab and Muslim immigrants have been subjected to fingerprinting and registration, and more than 5,000 foreign nationals have been imprisoned -- yet there has not been a single conviction for a terrorist crime in America. A handful of plots -- some deadly, some intercepted -- have plagued Europe and elsewhere, and even so, the death toll has been modest.

We have gone to war in two countries and killed tens of thousands of people. We have launched a massive domestic wiretapping program and created vast databases of information once considered private. Politicians and pundits have berated us about national security and patriotic duty, while encroaching our freedoms and sending thousands of young men off to die.

It is time to consider the hypothesis that dare not speak its name: we have wildly overreacted. Terrorism has been used by murderous groups for many decades, yet even including 9/11, the odds of an American being killed by international terrorism are microscopic. In general, international terrorism doesn't do much damage when considered in almost any reasonable context.

The capacity of al-Qaeda or of any similar group to do damage in the United States pales in comparison to the capacity other dedicated enemies, particularly international Communism, have possessed in the past. Lashing out at the terrorist threat is frequently an exercise in self-flagellation because it is usually more expensive than the terrorist attack itself and because it gives the terrorists exactly what they are looking for. Much, probably most, of the money and effort expended on counterterrorism since 2001 (and before, for that matter) has been wasted.

The terrorism industry and its allies in the White House and Congress have preyed on our fears and caused enormous damage. It is time to rethink the entire enterprise and spend much smaller amounts on only those things that do matter: intelligence, law enforcement, and disruption of radical groups overseas. Above all, it is time to stop playing into the terrorists' hands, by fear-mongering and helping spread terror itself.