Hardly Existential

It is misleading to use the positive results of counterterrorism spending as a key reason to reduce that same spending.

Matthew J. comments on

Hardly Existential

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An impressively large number of politicians, opinion makers, scholars, bureaucrats, and ordinary people hold that terrorism -- and al Qaeda in particular -- poses an existential threat to the United States. This alarming characterization, which was commonly employed by members of the George W. Bush administration, has also been used by some Obama advisers, including the counterterrorism specialist Bruce Riedel. Some officials, such as former U.S. Secretary of Homeland Security Michael Chertoff, have parsed the concept further, declaring the struggle against terrorism to be a "significant existential" one.

Over the last several decades, academics, policymakers, and regulators worldwide have developed risk-assessment techniques to evaluate hazards to human life, such as pesticide use, pollution, and nuclear power plants. In the process, they have reached a substantial consensus about which risks are acceptable and which are unacceptable. When these techniques are applied to terrorism, it becomes clear that terrorism is far from an existential threat. Instead, it presents an acceptable risk, one so low that spending to further reduce its likelihood or consequences is scarcely justified.

An unacceptable risk is often called de manifestis, meaning of obvious or evident concern -- a risk so high that no "reasonable person" would deem it acceptable. A widely cited de manifestis risk assessment comes from a 1980 United States Supreme Court decision regarding workers' risk from inhaling gasoline vapors. It concluded that an annual fatality risk -- the chance per year that a worker would die of inhalation -- of 1 in 40,000 is unacceptable. This is in line with standard practice in the regulatory world. Typically, risks considered unacceptable are those found likely to kill more than 1 in 10,000 or 1 in 100,000 per year.

At the other end of the spectrum are risks that are considered acceptable, and there is a fair degree of agreement about that area of risk as well. For example, after extensive research and public consultation, the United States Nuclear Regulatory Commission decided in 1986 that the fatality risk posed by accidents at nuclear power plants should not exceed 1 in 2 million per year and 1 in 500,000 per year from nuclear power plant operations. The governments of Australia, Japan, and the United Kingdom have come up with similar numbers for assessing hazards. So did a review of 132 U.S. federal government regulatory decisions dealing with public exposure to environmental carcinogens, which found that regulatory action always occurred if the individual annual fatality risk exceeded 1 in 700,000. Impressively, the study found a great deal of consistency among a wide range of federal agencies about what is considered an acceptable level of risk.

There is a general agreement about risk, then, in the established regulatory practices of several developed countries: risks are deemed unacceptable if the annual fatality risk is higher than 1 in 10,000 or perhaps higher than 1 in 100,000 and acceptable if the figure is lower than 1 in 1 million or 1 in 2 million. Between these two ranges is an area in which risk might be considered "tolerable."

These established considerations are designed to provide a viable, if somewhat rough, guideline for public policy. In all cases, measures and regulations intended to reduce risk must satisfy essential cost-benefit considerations. Clearly, hazards that fall in the unacceptable range should command the most attention and resources. Those in the tolerable range may also warrant consideration -- but since they are less urgent, they should be combated with relatively inexpensive measures. Those hazards in the acceptable range are of little, or even negligible, concern, so precautions to reduce their risks even further would scarcely be worth pursuing unless they are remarkably inexpensive.

If the U.S. Department of Homeland Security wants to apply a risk-based approach to decision-making, as it frequently claims it does, these risk-acceptance criteria seem to be most appropriate. To this end, the table below lists the annual fatality risks for a wide variety of these dangers, including terrorism.