The Transportation Security Administration (TSA) was created in response to the 9/11 attacks, which used airplanes as weapons. But the agency takes seriously the more expansive mission implied by the word transportation. Since 2007, the TSA has proudly used what it calls VIPR squads-for Visible Intermodal Prevention and Response-in places other than airports. VIPR squads have been deployed over 8,000 times a year for the past two years.

By allying with other law enforcement agencies, such as the U.S. Border Patrol, the TSA has crept into law enforcement areas unrelated to national security or the war on terror, including immigration, drugs, and prostitution. Sometimes VIPR searches are done on people as they exit trains. That's hard to justify on the grounds of transportation security.

VIPR teams feel they are beyond the search protections of the Fourth Amendment. As The New York Times reported in August, TSA officials claim "the random searches are 'special needs' or 'administrative searches' that are exempt from probable cause because they further the government's need to prevent terrorist attacks." VIPR, the Times reports, "has a $100 million annual budget…increasing to several hundred people and 37 teams last year, up from 10 teams in 2008." The TSA won't say whether a VIPR team has ever uncovered or foiled a terror plot.