This straightforward restoring bill is about promoting consumer rights. When consumers finish the terms of their contract, they should be able to keep their phones and make their own decision about which wireless provider to use.
– Sen. Patrick Leahy (D-VT)
The bill only allows the unlocking until the Library of Congress meets again next year.
Senate passes bill to allow ‘unlocking’ cell phones
Specifically, the bill would enable consumers to unlock cellphones that they've paid for in order to use them on any wireless network. The bill would leave illegal the removal of digital rights management (DRM) controls for the purpose of copyright infringement.
Members of Congress finally introduce serious DMCA reform
It's been illegal to unlock a cellphone since early 2013. In 2013 the Library of Congress (LOC), which has the power to carve out exemptions in the copyright law known as the DMCA, decided to phase out an exemption that had allowed Americans to legally unlock their cellphones. The LOC meets again in 2015 to review policy.
Federal Register, Volume 77 Issue 208 (Friday, October 26, 2012)