• by Wendy Davis , Staff Writer @wendyndavis, January 25, 2013

As of Sunday people who purchase smartphones will no longer be able to legally unlock the devices without carrier approval, thanks to the Librarian of Congress.

Every three years, the Librarian of Congress issues exemptions to a provision of the Digital Millennium Copyright Act that makes it illegal to circumvent digital rights management software. In the past, the officials granted an exemption for purposes of unlocking smartphones.

But in October, the U.S. Copyright Office decided not to renew that exemption, which will expire on Saturday. Consumers Union, MetroPCS and others unsuccessfully argued to the Copyright Office that allowing people to unlock phones didn't threaten any valid copyright interest in the software that tied phones to carriers.

On the other side of the issue, the trade group CTIA asked the authorities to criminalize unlocking. The group said that wireless carriers subsidize some smartphones because the carriers expect the devices to remain on the network.

The authorities ruled against renewing the exemption, which was first granted in 2006. The  official report said the exemption wasn't necessary because "the marketplace has evolved such that there is now a wide array of unlocked phone options available to consumers."

That's probably true, given that some carriers have been moving away from subsidies. Still, it's worth asking why a law aimed at preventing piracy should be interpreted to prevent people from tinkering with their devices in order to change wireless carriers.

The Copyright Office also ruled last year that people can't legally jailbreak tablets. But users are still allowed to jailbreak their iPhones. Doing so allows people to install unapproved software or apps.