Now go write on the Insta-blackboard 100 times, “Correlation is not causation.”

This is the sort of reasoning that proves that antibiotics cause infections. After all, if you look at people receiving antibiotics, they have more infections than people who aren’t.

If Bush’s poll numbers are lower when there are lots of terror alerts, that could show either that: (1) terror alerts push his poll numbers down or that: (2) when his poll numbers go down, Ashcroft and Ridge get the high sign to launch a terror alert to stop the decline; or that (3) Bush’s popularity has been declining over time, and the number of terror alerts has been increasing, for substantially unrelated reasons, and the apparent correlation is entirely spurious.

My bet would be on #3.

The one thing the data don’t do is disprove the suspicion that the alerts are partly politically motivated. (I’ll give you one guess about who’s claiming that it does.)

When the Secretary of Homeland Security, a professional politician with no actual security credentials, credits the “President’s leadership” as part of his speech announcing the latest alert, it’s surely not far-fetched to think he might know it’s an election year.

I think John Kerry did the right thing, substantively as well as politically, in disowning Howard Dean’s comments on this; public figures need to be careful of what they say, and given that no one outside the government knows how solid the basis for the warnings might be, the rest of us have no choice but to act as if the warnings are real. After all, one of these days there will be a wolf, even if we know that Peter (George)(Tom)(John) is somewhat veridically challenged.

But that’s not the same as saying that Dean was wrong. This is an Administration that has lived by Mark Twain’s maxim: “Tell the truth, or trump. But take the trick.” If people are skeptical of terror warnings coming out of this Administration, it’s not without reason.

Author: Mark Kleiman

Professor of Public Policy at the NYU Marron Institute for Urban Management and editor of the Journal of Drug Policy Analysis. Teaches about the methods of policy analysis about drug abuse control and crime control policy, working out the implications of two principles: that swift and certain sanctions don't have to be severe to be effective, and that well-designed threats usually don't have to be carried out. Books: Drugs and Drug Policy: What Everyone Needs to Know (with Jonathan Caulkins and Angela Hawken) When Brute Force Fails: How to Have Less Crime and Less Punishment (Princeton, 2009; named one of the "books of the year" by The Economist Against Excess: Drug Policy for Results (Basic, 1993) Marijuana: Costs of Abuse, Costs of Control (Greenwood, 1989) UCLA Homepage Curriculum Vitae Contact: