It’s something of an established principle in many countries that legal internet traffic should be treated equally. But does net neutrality trump the US constitution? A court may soon have to give the answer.

The Federal Communications Commission has regularly argued that it has a legal responsibility to regulate the Internet to keep it open, clamping down on practices such as deliberately blocking or slowing content of particular types or from particular providers.

Verizon, however, takes the view that it’s not the government’s job to tell it how to carry data over cables that it owns. It maintains the right to, for example, charge a fee to a major website in return for giving it higher priority and thus a faster or more reliable connection to site visitors.

At stake is the FCC’s Open Internet Order, a set of rules issued in 2010 that largely banned any activity that would contravene the net neutrality principle. Firms are allowed to breach the principle solely for “reasonable network management” and must publicly detail their policies on this point.

Verizon is now challenging that order, not so much on the details of the order itself, but rather on the wider issue of whether the FCC has the authority to make such rules. One of its main argument is that communications are legally classed in one of two categories: Title 1, which is for information services and Title 2, which is for telecommunications services.

At the moment, broadband is officially classed a Title 1, severely limiting the FCC’s rulemaking power. The commission has argued it should be reclassified as Title 2 which would give it more regulatory power, the legal logic being its more important to ensure a level playing field in communication than it is in broadcasting. It’s also suggested splitting the classification, meaning the physical aspects such as routing data are Title 2 while the content itself is Title 1.

To make things more confusing, that reclassification process has stalled because of arguments about whether doing so requires a change in the law (and thus Congressional approval) rather than the FCC making the decision itself.

According to Verizon, the net neutrality debate is a matter of constitutionally protected free speech: it likens its right to decide which content to give priority transmission to, and which to block completely, to the way a newspaper decides which stories and writers to include and which to leave out or bury on page 32.

Kevin Bankston of the Center for Democracy and Technology challenges that in legal advice submitted to the court, noting that Verizon and its competitors have previous argued they exercise no “editorial” control and thus can’t, for example, be held responsible for copyright infringement online.

The case is being heard by the U.S. Court of Appeals for the District of Columbia Circuit, though given Verizon’s mention of the Constitution, it’s almost certain the loser will try to take it to the Supreme Court. While there will no doubt be plenty of technical detail in the case, it does seem to come down to balancing two key principles: the right of private companies to deal with customers how they see fit against the duty of the government to protect the open nature of the Internet by enforcing a level playing-field.