In a major blow to the cause of media ownership deregulation, the Department of Justice Thursday announced that the Federal Communications Commission and Justice will not appeal the FCC’s media ownership case to the Supreme Court.

Industry sources said the decision does not prohibit media companies from pursuing their own Supreme Court challenges in the case. Those appeals are due in the high court Jan. 31. “But it’s highly unlikely that the Supreme Court would agree to hear the case without the government involved,” said Andrew Schwartzman, president of the Media Access Project.

In a series of statements, watchdog groups said the announcement all but ensures that the FCC will now have to fix deregulation that was thrown out last year by a federal appeals court in Philadelphia.

“The FCC, in redoing its ownership rules, must ensure that the rules encourage a diversity of voices and truly serve the citizens,” said Chellie Pingree, president of Common Cause. “The ball is now back in the FCC’s court,” Democratic FCC Commissioners Michael Copps and Jonathan Adelstein said in a joint statement. “The commission should seize this second chance to do the right thing.”