The National Football League and Major League Baseball are urging the Supreme Court to consider shutting down Internet video company Aereo.
In a brief filed with the court, the sports leagues backed a petition from a coalition of television broadcasters calling for the Supreme Court to review the case.
The leagues argued that Aereo threatens the millions of dollars they make every year in licensing deals with TV stations.
"The Court’s intervention is now necessary to restore clarity and certainty in this area and to prevent the unraveling of a marketplace built upon the licensing of rights rather than the expropriation of such rights through technological chicanery," lawyers for the NFL and MLB wrote.
Aereo, which is backed by media mogul Barry Diller, uses tiny antennas to pick up free over-the-air broadcast television signals and then transmits the video to its customers over the Internet. Customers pay a monthly fee to buy access to an antenna, which allows them to record and watch major network television on their mobile devices and computers.
CBS, NBC, ABC, Fox and other broadcasters have sued, arguing that Aereo must pay for permission to re-broadcast their signals, just like cable and satellite providers already do.
But the U.S. Court of Appeals for the 2nd Circuit ruled in April that Aereo's transmissions do not constitute a "public performance" under copyright law.
In their brief, the NFL and MLB warned that they could move all their games to cable channels like ESPN and TNT so "Aereo-like services cannot hijack and exploit their programming without authorization."
They claimed that Aereo's system of antennas "is neither technologically efficient nor innovative."
"It has no purpose other than to avoid compensating the copyright owners whose programming Aereo exploits," they wrote.
The leagues said they understand that many consumers want to be able to watch all NFL and MLB games, including on their mobile devices. But they argued that Aereo undermines existing, legitimate options such as NFL Sunday Ticket and MLB Extra Innings, which allow consumers to buy access to the games.
"The revenues from these packages are an important source of income that permits the Leagues and their member clubs to provide the entertainment product that millions of fans worldwide are able to enjoy," they argued.