A year ago, on the anniversary of the September 11, 2001, attacks by Al Qaeda on the United States, I argued that the U.S. overreacted to these horrific acts of terrorism. Today, I’m posting an edited version of that column, the gist of which–especially given the current highly emotional debate over violent U.S. intervention in Syria–remains all too relevant.

My conclusion that the U.S. overreacted to 9/11 is based in part on risk-benefit analyses by John Mueller, a political scientist at Ohio State University, and Mark Stewart, a civil engineer and authority on risk assessment at University of Newcastle in Australia. Mueller and Stewart note in Homeland Security Affairs that after 9/11, U.S. officials warned that we could expect many more such attacks, and that terrorism represents an “existential” threat, as the former Secretary of Homeland Security Michael Chertoff put it.

These fears triggered a surge in counterterrorism spending. Mueller and Stewart estimate that the response to 9/11 by federal, state and local governments as well as private corporations has totaled $1 trillion. The costs include measures such as beefed up intelligence, hardening of facilities and more robust airport screening but exclude the wars in Afghanistan and Iraq. Even granting that terrorism evokes powerful emotions and hence deserves more attention than other dangers, Mueller and Stewart contend, “a great deal of money appears to have been misspent and would have been far more productive–saved far more lives–if it had been expended in other ways.”

In general, government regulators around the world view fatality risks–say, from nuclear power, industrial toxins or commercial aviation–above one person per million per year as “acceptable.” Between 1970 and 2007, Mueller and Stewart assert in Foreign Affairs, a total of 3,292 Americans (not counting those in war zones) were killed by terrorists, resulting in an annual risk of one in 3.5 million. Americans were more likely to die in an accident involving a bathtub (one in 950,000), a home appliance (one in 1.5 million), a deer (one in two million) or on a commercial airliner (one in 2.9 million). [See table.]

The global mortality rate of death by terrorism is even lower. Worldwide, terrorism killed 13,971 people between 1975 and 2003, an annual rate of one in 12.5 million. Since 9/11 acts of terrorism carried out by Muslim militants outside of war zones have killed about 300 people per year worldwide. This tally includes attacks not only by al Qaeda but also by “imitators, enthusiasts, look-alikes and wannabes,” according to Mueller and Stewart.

Defenders of U.S. counterterrorism efforts argue that they have kept casualties low by thwarting attacks. But investigations by the FBI and other law enforcement agencies suggest that 9/11 may have been an outlier–an aberration–rather than a harbinger of future attacks. Muslim terrorists are for the most part “short on know-how, prone to make mistakes, poor at planning” and small in number, Mueller and Stewart state. Although still potentially dangerous, terrorists hardly represent an “existential” threat on a par with those posed by Nazi Germany or the Soviet Union.

In fact, Mueller and Stewart suggest in Homeland Security Affairs, U.S. counterterrorism procedures may indirectly imperil more lives than they preserve: “Increased delays and added costs at U.S. airports due to new security procedures provide incentive for many short-haul passengers to drive to their destination rather than flying, and, since driving is far riskier than air travel, the extra automobile traffic generated has been estimated to result in 500 or more extra road fatalities per year.”

The funds that the U.S. spends on counterterrorism should perhaps be diverted to other more significant perils, such as industrial accidents (one in 53,000), violent crime (one in 22,000), automobile accidents (one in 8,000) and cancer (one in 540). “Overall,” Mueller and Stewart write, “vastly more lives could have been saved if counterterrorism funds had instead been spent on combating hazards that present unacceptable risks.”

Mueller and Stewart’s analysis is conservative, because it excludes the most lethal and expensive U.S. responses to 9/11. Al Qaeda’s attacks helped provoke the U.S. into invading and occupying two countries, at an estimated cost of several trillion dollars. The wars in Afghanistan and Iraq have resulted in the deaths of some 10,000 American soldiers and contractors so far–more than three times as many Americans as were killed on September 11, 2001–as well as tens of thousands of Iraqis and Afghans.

The U.S. has also damaged its moral reputation by imprisoning without trial, torturing and assassinating alleged terrorists even in nations, such as Pakistan and Yemen, with which we are not at war. All these actions have helped arouse rather than quell anti-American sentiment among Muslims and others. In spite of its economic woes, the U.S. has doubled its annual defense spending in the past decade, which is now roughly equal to that of all other nations combined.

Osama bin Laden, who was finally killed by U.S. forces on May 2, 2011, never again pulled off an attack as cataclysmic as the one on 9/11. But he didn’t have to, because we–the U.S.–wreaked so much destruction ourselves. In 2004 bin Laden gloated that he was “bleeding America to the point of bankruptcy,” the same strategy with which he and other jihadists–with U.S. backing–drove Soviet troops from Afghanistan.

Mueller and Stewart–who present a detailed critique of counterterrorism policies in Terror, Security and Money: Balancing the Risks, Benefits and Costs of Homeland Security (Oxford University Press, 2011)–note that a major obstacle to more rational policies is a shortage of “that oxymoronic commodity,” political courage.

When it comes to security issues, reason and imagination also seem to be in short supply among our leaders, who are far too quick to resort to violence as a response to violence. I hope that, as the traumatic memory of 9/11 recedes, our leaders begin devising smarter policies toward terrorism and other security threats–as well as to crises like the one in Syria.

*Previous headline read: “Did United States Overreact to 9/11 Terror Attacks?”