Though 80 percent of retail outlets voluntarily chose to observe the ESRB guidelines and not sell M- and AO-rated games to minors, the ratings did not have force of law. That changed in 2005, when California enacted a law to make renting or selling an M-rated game to a minor an offense enforced by fines. The law was immediately challenged by the industry and struck down by a lower court as unconstitutional. California petitioned the Supreme Court to hear the case. In a landmark decision handed down in 2011, the Supreme Court granted electronic games speech protections afforded by the First Amendment. According to the opinion written by Justice Antonin Scalia, video games communicate ideas worthy of such protection:

Like the protected books, plays, and movies that preceded them, video games communicate ideas—and even social messages—through many familiar literary devices (such as characters, dialogue, plot, and music) and through features distinctive to the medium (such as the player’s interaction with the virtual world).49

Scalia even mentions Mortal Kombat in footnote 4 of the decision:

Reading Dante is unquestionably more cultured and intellectually edifying than playing Mortal Kombat. But these cultural and intellectual differences are not constitutional ones. Crudely violent video games, tawdry TV shows, and cheap novels and magazines are no less forms of speech than The Divine Comedy. . . . Even if we can see in them “nothing of any possible value to society . . . they are as much entitled to the protection of free speech as the best of literature.”

With the Supreme Court decision, electronic games achieved the same First Amendment protection afforded to other mass media. However, as in the music, television, and film industries, First Amendment protections will not make the rating system for the gaming industry go away. Parents continue to have legitimate concerns about the games their children play. Game publishers and retailers understand it is still in their best interest to respect those concerns even though the ratings cannot be enforced by law.