The US Senate on Wednesday is scheduled to vote on whether to reinstate the Federal Communications Commission's net-neutrality rules.

Though the vote on the measure has been expected for months, its outcome is uncertain. Fifty senators have declared their support for it — one shy of the majority needed to pass it.

The Senate will vote on a resolution under the Congressional Review Act, a law that allows Congress, with a simple-majority vote in both houses, to overturn new regulations by federal agencies within 60 legislative days of implementation.​

The resolution will seek to overturn a rule voted on by the FCC in December that eliminated most of its net-neutrality regulations.

Net neutrality is the principle that all traffic on the internet should basically be treated the same. While the name for the principle isn't that old, the basic idea predates the internet and has its roots in the telephone and telegraph networks and even older services.