Here's the scenario: you return from an overseas trip and find yourself facing US Customs officers in an airport. They see your laptop, demand that you turn it on, then take it from you and start rifling through its contents. They have no reason for the search, and they can and do look for anything they like. Is this legal? In a new decision, the Ninth Circuit says yes.

In a Monday ruling, the judges considered an appeal from one Michael Arnold. Arnold was 43 when he returned to the US from the Philippines in July 2005, and he showed up at LAX with a laptop, separate hard drive, flash drive, and six compact discs. A Customs and Border Patrol agent asked Arnold to fire up the machine, then decided to take a look through two folders on the machine's desktop, labeled "Kodak Pictures" and "Kodak Memories." Why the officer did this is not clear, but he found a picture "that depicted two nude women." Further searching turned up images that appeared to be child pornography, and Arnold's computer was seized.

A court case followed in which Arnold argued that the results of this search should not be allowed, as they were unreasonable under the Fourth Amendment. A district court bought Arnold's argument that a laptop was different from normal closed containers like luggage, which are routinely examined by border agents without particular cause. Arnold claimed that a laptop was more like "home" and "the human mind" than a typical closed container and that searching it required a reason. The district court agreed.

But the Ninth Circuit took the district court's logic out behind the woodshed and thrashed it with a willow switch. The judges noted that precedent already allows searches of 1) briefcases and luggage, 2) a purse, wallet, or pocket, 3) papers found in pockets, and 4) pictures, films, and other graphic material. In fact, the Supreme Court allows border agents wide latitude, only drawing the line at searching the "alimentary canal" of a suspect without reasonable suspicion (seriously).

Given that latitude and the basic legal principle that a nation has the sovereign right to "protect its territorial integrity," the Ninth Circuit concluded that Arnold's case could go forward with the evidence gleaned from his laptop. Considering the various sorts of highly personal information toted about on most laptops, the decision might be correct but still feels a bit unsettling; News.com's Declan McCullagh put together a helpful guide to laptop border security last month that might reassure travelers who aren't thrilled about the idea of some official scanning tax returns, business secrets, and e-mail without a reason.

We've already taken a thorough look at how devices like iPhones and laptops can suddenly deliver an entire life's worth of data into the hands of the feds in a way that was never possible twenty years ago. While the implications of such searches are wide-ranging, the authority isn't actually new; the Ninth Circuit already ruled the same way back in 2006 in another case involving laptop child porn and border agents.

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