Suppose you're returning home from a vacation in Cancun. A customs agent asks you to open your suitcase so he can check its contents. So far, so good. Now, the agent asks you to log on to your laptop so he can read your e-mails and personal files and examine which Web sites you've visited. He makes a copy of your hard drive so the government can comb through its contents. You've done nothing to give the agent any cause for suspicion. That can't be legal - can it? Until recently, it would not have been allowed. Long-standing customs directives prohibited agents from reading travelers' personal documents unless they reasonably suspected them to be merchandise or evidence of illegal activity. Then the Bush administration changed the rules, allowing agents to review and analyze" the contents of electronic devices, including laptops, cell phones and BlackBerrys "absent individualized suspicion." Agents also could make copies of the devices' contents and share them with other government agencies. In a Senate Judiciary Committee hearing in May, Secretary of Homeland Security Janet Napolitano promised to review the policy. Homeland Security has now released a new policy - and it is the same as the Bush policy in almost every relevant respect. The government may still search electronic devices without reasonable suspicion, retain copies indefinitely to complete its search and share information with other agencies. Both administrations have cited national security to justify suspicionless searches. There's no evidence, however, that a suspicionless search has ever turned up a security threat.