Mozilla, Google, Facebook, Vimeo, advocacy groups, and others headed to court last Friday to protest a recent ruling of the U.S. Court of Appeals for the District of Columbia Circuit. The companies are spearheading an appeal in the fight for net neutrality, or the right to maintain an open Internet, without broadband provider manipulation of content.

Provider manipulation could include restricting Internet access to unpopular points of view, charging providers of specific sites more to show their content, or changing the connection speed when displaying certain material. Those against net neutrality believe that it negatively impacts competitive corporate investment in Internet services.

The October ruling by the D.C. Circuit supported the 2017 decision of the Federal Communications Commission under Trump appointee Ajit Pai to do away with net neutrality protections put in place during the Obama administration. Pai’s repeal also prevented states from determining their own net neutrality policies, which may now change, depending on the final ruling.

According to the Washington Post, Mozilla and other open-Internet advocates “argued the appeals court erred by overlooking a 2005 case that affirmed the agency’s power to decide how best to regulate telecom giants.” This longstanding and largely political battle is set to continue until a rehearing decision is made, and, most likely, long after that.