Homeland Security Secretary-designate Michael Chertoff is a big advocate of data mining as a tool to identify terrorists.In testimony presented three years ago at a Senate Banking Committee hearing on the financial war on terrorism, when he headed the Justice Department's criminal division, Chertoff characterized data mining as a promising tool to help thwart financing of terrorist efforts.

"We are using computers to analyze information obtained in the course of criminal investigations, to uncover patterns of behavior that, before the advent of such efficient technology, would have eluded us," he testified four months after the Sept. 11 terrorist attacks. "Through what has come to be called data mining and predictive technology, we seek to identify other potential terrorists and terrorism financing networks. In our search for terrorists and terrorist cells, we are employing technology that was previously utilized primarily by the business community."

Later in 2002, speaking at a Federalist Society panel in Washington, Chertoff defended the government's aggregation of large amounts of personal information in computer databases for law enforcement and national security, as recounted at the time by the National Journal's Technology Daily. Chertoff--who helped author the Patriot Act, legislation critics say intrudes on civil liberties--defended data-mining by the government, comparing it to the type of information that Amazon.com aggregates about an individual user's book preferences. "It is hard to say that my privacy has been significantly invaded because the government, in protecting me, can use the same technologies as people who want to market to me," Chertoff said.

Speaking on the same panel, according to Technology Daily, American Civil Liberties Union President Nadine Strossen called data mining the "power to snoop on every act of every American." Chertoff retorted that data analysis had "obvious utility" in detecting "certain types of money flows" in terrorist financing.