On Friday, the House of Representatives passed legislation to allow people to unlock their cell phones in order to take them to a different wireless carrier. The Senate approved the same legislation earlier this month, which means the bill is headed to President Obama for his signature.

The legislation became necessary after a controversial 2012 decision from the Librarian of Congress that raised the possibility that taking your cell phone to a new wireless carrier could violate copyright law.

Unfortunately, Congress has chosen the narrowest possible approach to addressing the issue. Lawmakers have refused to rethink the Digital Millennium Copyright Act, the law that created the problem in the first place. That's a shame because cell phone unlocking is far from the only case where the DMCA has created unnecessary headaches for people.

The legislation wouldn't provide exemptions for other innocuous activities that are restricted by the DMCA

Congress enacted the DMCA in 1998 as an anti-piracy measure. Hollywood and the recording industry were pressuring technology companies to develop anti-piracy technology called digital rights management to prevent customers from copying music and movies. The DMCA made it illegal to tamper with DRM or to distribute devices or software that could be used to circumvent it.

But clever lawyers soon realized that the DMCA's no-tampering rule could be used to restrict user rights in ways had nothing to do with the law's anti-piracy mission:

The DMCA has been invoked to stop people from selling third-party garage door openers and third-party printer cartridges, though courts eventually ruled for the defendants in both cases.

garage door openers third-party printer cartridges, The DMCA was successfully invoked against a company that helped people cheat in the online game World of Warcraft.

helped people cheat The DMCA makes it difficult for customers with vision or hearing problems to get accessible versions of copyrighted content. Accessibility tools often require content to be in open formats, but software to convert DRMed movies or ebooks into open formats is illegal.

The DMCA makes it more difficult for people who purchase content on one media platform (such as iTunes) to transfer it to another.

There are concerns that the DMCA could be invoked by auto companies to bar unauthorized mechanics from working on their cars.

In an effort to address these kinds of concerns, the DMCA gives the Librarian of Congress (currently James Billington) the power to grant exemptions from the DMCA's anti-circumvention rules. These exemptions must be renewed every three years.

But the Librarian has been stingy and inconsistent in its use of its exemption power. The most recent rule, approved in 2012, only granted five narrow exemptions. The 2012 rules make it legal for blind users to circumvent DRM on ebooks. But supplying users with the necessary software remains illegal. The 2012 rules allowed jailbreaking (jailbreaking allows users to run unauthorized software, while unlocking allows users to take a phone to another carrier) of iPhones, but jailbreaking iPads remains illegal.

The legislation Congress approved focuses narrowly on the cell phone unlocking issue. It wouldn't provide exemptions for other innocuous activities that are restricted by the DMCA. And it doesn't rethink the bizarre system in which the Librarian of Congress — an unelected official most people have never heard of — has arbitrary power to decide, every three years, how people can use a wide variety of digital devices.

The public furor over cell phone unlocking was an opportunity for a long-overdue re-think of the DMCA. But Congress is blowing that opportunity, fixing the most glaring symptom of the DMCA's dysfunction without considering a broader overhaul of the DMCA.