After September 11, most Americans felt that some tradeoffs between personal liberty and national security were warranted, and I still believe this was a correct feeling. But in this thought-provoking article, security expert Bruce Schneier warns that we need to make sure the people in charge of national security don’t have a skewed perspective on how far those tradeoffs should go: Slouching toward Big Brother.

In December, a provision slipped into an appropriations bill allowing the FBI to obtain personal financial information from banks, insurance companies, travel agencies, real estate agents, stockbrokers, the U.S. Postal Service, jewelry stores, casinos and car dealerships without a warrant—because they’re all construed as financial institutions. Starting this year, the U.S. government is photographing and fingerprinting foreign visitors coming into this country from all but 27 other countries.

I’m not sure I agree the fingerprinting of foreign visitors is a bad thing, but allowing the FBI to gather personal information from all those agencies without a warrant is definitely disturbing.

Schneier argues that it’s not a matter of the Republicans or Democrats being in charge; it’s a matter of the police being in charge.

…The Department of Justice, fueled by a strong police mentality inside the administration, is directing our nation’s political changes in response to Sept. 11. And it’s making trade-offs from its own subjective perspective—trade-offs that benefit it even if they are to the detriment of others.

From the point of view of the Justice Department, judicial oversight is unnecessary and unwarranted; doing away with it is a better trade-off. They think collecting information on everyone is a good idea because they are less concerned with the loss of privacy and liberty. Expensive surveillance and data-mining systems are a good trade-off for them because more budget means even more power. And from their perspective, secrecy is better than openness; if the police are absolutely trustworthy, then there’s nothing to be gained from a public process.

When you put the police in charge of security, the trade-offs they make result in measures that resemble a police state.

Bruce Schneier is the author of a book about security which I’ve read and highly recommend; a very entertaining and readable explanation of the basic concepts of security, with sensible guidelines for evaluating risks and tradeoffs intelligently: Beyond Fear: Thinking Sensibly about Security in an Uncertain World.