The US Supreme Court ruled Monday that a California law banning the sale or rental of violent videogames to minors was unconstitutional and a violation of free speech protections.

The top US court, in a 7-2 ruling, upheld a lower court judgment that struck down a 2005 California law that made retailers subject to fines of $1,000 for selling or renting videogames labeled as violent to anyone under the age of 18.

"Like the protected books, plays, and movies that preceded them, videogames communicate ideas -- and even social messages -- through many familiar literary devices," said Justice Antonin Scalia, author of the majority opinion.

"That suffices to confer First Amendment protection" to videogames under the US Constitution, Scalia said.

The California state law banning videogame sales to minors was overturned by a lower court in 2007 as infringing on free speech.

That ruling was upheld by a higher court in 2009. Then California governor Arnold Schwarzenegger appealed the case to the Supreme Court.

The law defines a violent videogame as one that depicts "killing, maiming, dismembering, or sexually assaulting an image of a human being," though it does not prevent a parent or guardian from purchasing a game for their child.

Opponents of the law argued that it restricted freedom of expression and was unnecessary because the Entertainment Software Rating Board rates thousands of games a year as to age appropriateness, providing parents with the ability to determine if a game is right their child.

The Supreme Court said the ESRB ratings do help prevent some particularly violent games from getting into the hands of children.

"This system does much to ensure that minors cannot purchase seriously violent games on their own, and that parents who care about the matter can readily evaluate the games their children bring home," the court said.

Opponents of the California law argued that minors should have the same access to potentially violent videogames as they currently do to movies or books with similarly graphic content.

The Supreme Court noted that many popular children's books contain gory material.

"Certainly the books we give children to read -- or read to them when they are younger -- contain no shortage of gore," the court said.

"Grimm's Fairy Tales, for example, are grim indeed," it said. "Cinderella's evil stepsisters have their eyes pecked out by doves. And Hansel and Gretel (children!) kill their captor by baking her in an oven."

The court also said there was no "compelling" evidence to show a link between exposure to violent videogames and harmful effects on children.

"These studies have been rejected by every court to consider them, and with good reason: They do not prove that violent videogames cause minors to act aggressively," the court said.

"California's effort to regulate violent videogames is the latest episode in a long series of failed attempts to censor violent entertainment for minors," it said. "Even where the protection of children is the object, the constitutional limits on governmental action apply."

The Supreme Court ruling was welcomed by the Entertainment Software Association (ESA) and the Entertainment Merchants Association (EMA).

"This is a historic and complete win for the First Amendment and the creative freedom of artists and storytellers everywhere," ESA president and chief executive Michael Gallagher said in a statement.

EMA president and chief executive Bo Andersen said "freedom of expression has been vindicated."

"There now can be no argument whether videogames are entitled to the same protection as books, movies, music, and other expressive entertainment," he said.