The National Football League and Major League Baseball are trying to convince the Supreme Court to grant broadcasters’ petition to challenge Aereo, a startup that enables unauthorized streaming of local broadcast signals. The NFL and MLB filed an amicus brief that suggests that if Aereo is not challenged, sports programming will likely switch over to cable. Broadcasters assert that Aereo undermines their ability to collect retransmission fees.

“If copyright holders lose their exclusive retransmission licensing rights and the substantial benefits derived from those rights when they place programming on broadcast stations, those stations will become less attractive mediums for distributing copyrighted content,” the leagues said in their brief. “The option for copyright holders will be to move that content to paid cable networks (such as ESPN and TNT) where Aereo-like services cannot hijack and exploit their programming without authorization.”

The leagues also noted the significance of important federal interest in their fight to protect over-the-air broadcasting.

“The leagues also argued that Aereo puts the U.S. in violation of international treaties prohibiting the retransmission of broadcast signals over the Internet without consent of program or station owners. It also said that, given a 2nd Circuit Court of Appeals ruling, Aereo could create packages of sports programming for free while the leagues create such arrangements in exclusivity,” reports Variety.

“The court’s intervention is now necessary to restore clarity and certainty in this area and to prevent the unraveling of marketplace built upon the licensing of rights rather than the expropriation of such rights through technological chicanery,” the brief explains.

In defense, Aereo claims that their service is a legal private transmission as opposed to a public performance in violation of the Copyright Act. They have not yet filed a reply brief.