In a huge victory for President Cristina Fernandez, Argentina's Supreme Court ruled Tuesday that the government can force private news media monopolies to break themselves apart if they exceed audience limits.

The ruling gives the green light to the country's four-year-old broadcast media law. It is a bitter defeat for Grupo Clarín, which has been a leading voice against her administration and will likely be forced to sell off key properties.

Among other restrictions, the 2009 law limits cross-ownership of media companies and says no TV network can command more than 35 percent of the nation's viewers and bars the same company from owning more than one or two radio stations in a single municipality.

The state has an unquestionable role in protecting public discourse by preventing monopoly power in the media industry, the court ruled.

"As ideas and information represent goods that are distributed through the media, if there is concentration, only some ideas or some information will reach the public, seriously harming public debate and the plurality of opinions," the court said. "All of this demands the active protection of the State."

Clarín is one of Latin America's largest media companies, with interests in newspapers, magazines, a nationwide television network and broadcast TV and radio stations. It would be forced to sell off its lucrative cable TV licenses once the law is implemented.

The Buenos Aires stock exchange suspended trading in the company's shares after they dropped nearly 6 percent due to the ruling.

By a four-three vote, the justices approved the law in its entirety, including four articles that seek to eliminate existing concentrations of media power. Two other judges approved the law in general while disagreeing on some of these articles. Only one declared the entire law unconstitutional.

Clarin says the law is unfair because it applies no limits to competitors that deliver news, internet access and other media services through telephone wires or by satellite to consumers nationwide.

Jaime Mantilla, president of the Inter-American Press Association, said that even before the ruling, Argentina's government has employed indirect censorship by rewarding or punishing media companies with subsidies, government advertising and access to information.

But government supporters celebrated, calling the ruling a victory for diversity and freedom of expression in a media landscape too often dominated by private interests. Martin Sabbatella, appointed by Fernandez to run the new broadcast media regulation agency, called it "a triumph of democracy."

The 392-page ruling also warned the government that it must act fairly to all media companies, and said many questions won't be resolved until the law is implemented, presaging future legal battles. But the justices also said that it's up to Congress, not the courts, to update the law as needed to keep up with changing technologies or other shortcomings.

The court's majority said that license holders must be compensated when forced to divest their stations, that subsidies currently going to pro-government media should be redistributed fairly and transparently, that state-owned media must be more than government mouthpieces, that the broadcast media regulator must be independent of executive power, and that any efforts to reform Argentina's media industry must be done fairly and with due process.

"This law and its goal of achieving plurality and diversity in mass media would be senseless without the existence of transparent public policies in terms of official publicity," the justices said.

When "the state affects freedom of expression, whether through subsidies, distributing official advertising or any other benefit, the communication media become mere instruments of support for a political movement, or a way to eliminate dissent and an open debate of ideas."

Based on reporting by The Associated Press.

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