Most people have probably figured out that handheld gadgets and laptops know us better than our spouses do. They know whom we talk to, which Web sites we visit, whose e-mail we ignore, and with a little extra smarts, they could probably offer an educated guess about what we'd prefer for dinner tonight.
To snatch these useful little devices from our homes, police need warrants. But if we happen to be arrested with gadgets in our pocket or purse, police and prosecutors say they have the right to peruse what could be gigabytes of data for potentially incriminating files or photographs.
That vast collection of data lures police as surely as a $78 Blu-ray player lures Wal-Mart shoppers, and courts have split on whether it's permissible or not.
The U.S. Constitution's Fourth Amendment, of course, prohibits "unreasonable" searches and seizures. In general, a search without a warrant is viewed as unreasonable; searches when a person is arrested are an exception to that general rule.
But a 32 GB iPhone can store more information than can be found in most home bookshelves and filing cabinets (the complete works of Shakespeare takes up only about 1/100th of a gigabyte). So an analogy to the old you-can-search-through-someone's-pocket rule doesn't really seem to apply.
Also, if courts acquiesced to prosecutors' arguments, what's to stop police from searching through the entire contents of a suspect's laptop upon arrest? If judges declare that a laptop is off-limits, what about a tablet PC or a possible Apple tablet?
Here are some excerpts from Tuesday's opinion, which is short and worth reading on your own:
Cell phones are neither address books nor laptop computers. They are more intricate and multifunctional than traditional address books, yet they are still, in essence, phones, which makes them distinguishable from laptop computers. Although cell phones cannot be equated with laptop computers, their ability to store large amounts of private data gives their users a reasonable and justifiable expectation of a higher level of privacy in the information they contain. Once the cell phone is in police custody, the state has satisfied its immediate interest in collecting and preserving evidence and can take preventive steps to ensure that the data found on the phone is neither lost nor erased. But because a person has a high expectation of privacy in a cell phone's contents, police must then obtain a warrant before intruding into the phone's contents...
A search of the cell phone's contents was not necessary to ensure officer safety, and the state failed to present any evidence that the call records and phone numbers were subject to imminent destruction. We therefore hold that because a cell phone is not a closed container, and because an individual has a privacy interest in the contents of a cell phone that goes beyond the privacy interest in an address book or pager, an officer may not conduct a search of a cell phone's contents incident to a lawful arrest without first obtaining a warrant.
The Ohio court's view differs from other decisions I wrote about earlier this year. In January, two federal district judges split over warrantless searches of gadgetry upon arrest. An earlier opinion from the 5th Circuit sided with police; a 2007 decision from a federal judge in San Francisco reached the opposite conclusion.
It's not just a question of perusing handheld devices -- in some cases, cops will extract their complete contents. A 2007 case involved a truck driver and a Kansas highway patrol trooper who copied the complete contents of the suspect's two cell phones -- which a Kansas district judge said was perfectly fine.
The good news is that, as judges become familiar with iPhones, Android phones, and other capacious handhelds that can hold a user's entire electronic life, they're becoming more sophisticated about interpreting how the Fourth Amendment applies. The bad news is that it might take them a while to get there.
Declan McCullagh is a senior correspondent for CBSNews.com. He can be reached at email@example.com and can be followed on Twitter as declanm. You can bookmark Declan's Taking Liberties site here, or subscribe to the RSS feed. Before becoming a CBS employee, Declan was the chief political correspondent for CNET, a reporter for Time, and Washington bureau chief for Wired.