The case, Brown vs Entertainment Merchants Association, ruled on a California law which limited the sale video games to minors if the game meets these three criteria:
1. "The range of options available to a player includes killing, maiming, dismembering, or sexually assaulting an image of a human being, if those acts are depicted"
2. In a manner that "[a] reasonable person, considering the game as a whole, would find appeals to a deviant or morbid interest of minors,"
3. Is "patently offensive to prevailing standards in the community as to what is suitable for minors,"
4. "causes the game, as a whole, to lack serious literary, artistic, political, or scientific value for minors."
The Supreme Court said "government lacks the power to restrict expression because of its message, ideas, subject matter, or content". And California never proved that video games meet the few exceptions to the First Amendment protection of speech.
"Psychological studies purporting to show a connection between exposure to violent video games and harmful effects on children do not prove that such exposure causes minors to act aggressively." (A recent study actually says violent games helped reduce the crime rate)
"California also cannot show that the Act’s restrictions meet the alleged substantial need of parents who wish to restrict their children’s access to violent videos." because the video game industry already voluntarily provides ratings for parents with the ESRB system.
I'm glad to hear video games have finally been given First Amendment protection and hopefully overzealous governments will stop trying to restrict their sale.
You can read the entire 72 page oral arguments and official decision on the US Supreme Court website.