The National Cable & Telecommunications Association has thrown its backing behind Cablevision Systems’ Supreme Court challenge to must-carry rules.

Cablevision filed its challenge in January, arguing that the level of competition in the industry is sufficient to justify lifting must-carry rules, which compel MSOs to carry local channels on their systems. Cablevision continues to argue that must-carry also infringes on cable companies’ free speech rights.

The issue at the moment is convincing the Supreme Court to take the case.

The NCTA just filed a friend of the court brief supporting Cablevision’s arguments, echoing Cablevision’s request for certiorari (certiorari is basically the Supreme Court’s right to examine the ruling of a lower court).

In its brief, the NCTA notes that “DirecTV and EchoStar are now the second- and third-largest providers of multichannel video programming, and the FiOS and U-verse offerings of telephone companies such as Verizon and AT&T are growing fast.”

This perhaps provides a clue as to why the NCTA decided to shuffle its list of top video providers last month.