A passenger-screening system designed to help capture terrorists could also be used to target people suspected of violent crimes, under a proposal approved by Department of Homeland Security officials.

Previously, government officials said the surveillance system known as CAPPS II would be used only to target potential terrorists and their allies — limits intended to assuage concerns about the program’s impact on privacy and civil liberties.

Plans called for using commercial information services to sort through demographic and marketing data to establish whether passengers are “rooted in the community.” Classified government computers would then review passengers with questionable reports for signs of terrorist intent.

The new proposal shows that officials intend to use the system — potentially the largest surveillance network created by the government — more broadly to keep dangerous people off planes. That could include people wanted for domestic terrorism or violent crimes.

Anyone flagged by the system would receive extra screening or, in some circumstances, be detained.

A draft of a notice to be published in the Federal Register says “such information may be shared between law enforcement agencies and the Department of Homeland Security and appropriate action may be taken.” The document was reviewed by White House officials and signed by Homeland Security Secretary Tom Ridge several days ago.

The document is the latest turn in the belabored creation of CAPPS II, a system that Transportation Secretary Norman Y. Mineta described a year ago as the “the foundation” on which all other, more public security measures depend.

Officials envision deploying CAPPS II — short for the second-generation computer-assisted passenger pre-screening system — to screen truckers, railroad conductors and other transportation workers.

Although officials had said CAPPS II would be operational by now, it has been delayed by questions about the proper technology and its potential intrusiveness.

Civil libertarians complained earlier this year when Transportation Department lawyers issued a proposal that left open the possibility that the government could collect and keep a wide variety of records for decades.

While critics conceded that the new proposal narrows the use and collection of personal information, they contended that it appears to expand the potential applications of CAPPS II.

David L. Sobel, general counsel at the Electronic Privacy Information Center, said he worries that CAPPS II will become a “massive enforcement mechanism.”

“It opens the door for invasive background checks on all citizens,” Sobel said.

James X. Dempsey, executive director of the Center for Democracy and Technology, said the change shows that officials will be always be tempted to expand the program’s reach. “The system hasn’t even been launched yet, and they’re already thinking up other uses for it,” he said.

Transportation Security Administration officials declined to comment on the proposal.

Homeland Security officials believe they have struck a balance between the protection of airplanes and the privacy rights of individuals. The system will be tested this summer and could be phased in beginning in the fall.

Nuala O’Connor Kelly, the agency’s privacy officer, said the proposal is a significant improvement over previous plans because it limits the amount of information the government collects. The proposal would also give people a way to access records when questions arise about them.

“We have demonstrated we can both zealously defend the country and at the same time respect the liberties of the individual,” Kelly said.

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© 2003 The Washington Post Company

This is a CIR-assisted report. On leave from The Washington Post, O’Harrow is presently receiving support from CIR for his investigation of post-September 11 government surveillance, which will result in a book to be published by Free Press in 2004.