Every state in the nation prevents minors from legally buying cigarettes, beer or porn magazines. Now the U.S. Supreme Court must decide whether to add violent video games such as “Postal 2” to the tawdry list.

In a legal showdown set for Tuesday, the justices will hear arguments in a challenge to a 2005 California law that bars the sale or rental of violent video games to minors. They are reviewing two lower-court rulings that put the law on hold, saying it is too vague and runs afoul of the First Amendment.

The case has aroused the passions of both sides, from gamers who want the government to keep its nose out of policing video games to politicians and parents’ rights groups that believe states have a right to protect kids from graphic depictions of violence.

The justices have been reviewing more than the usual legal briefs. California sent them a five-minute clip of video game violence, while the video game industry delivered a number of games for them to spark up on PlayStations, including “Medal of Honor” and “Resident Evil 4.”

Other states are divided on the issue. Eleven states sided with California’s argument that the First Amendment does not apply to government efforts to insulate children from harmful material. But nine states backed the entertainment industry, saying that California’s law may be well-intentioned but would force law enforcement to become “culture critics” and “distract from (the) task of policing actual violence.”

Legal experts say the case is a tossup for the justices, who are often reluctant to create exceptions to free speech protections.

“It’s an uphill battle” for California, said Michael McConnell, a Stanford University law professor and former federal appeals court judge. “But they granted (review) for a reason, and a lot of justices will be at least concerned about the phenomenon of children being exposed to this.”

The high court case stems from a law written by state Sen. Leland Yee, D-San Francisco, and backed strongly by Gov. Arnold Schwarzenegger. It would prevent those younger than 18 from buying or renting video games that “appeal to a deviant or morbid interest of children and are patently offensive to prevailing community standards.” Retailers would face a $1,000 fine for violations. In addition, the law requires video game makers to put an “18” label prominently on excessively violent games.

The law was enacted to counter increasingly graphic video game violence and to address concerns that playing such games fosters aggression and violent behavior in children and teenagers. “Call of Duty: Modern Warfare 2,” for example, added an optional level where players watch terrorists massacre civilians at an airport, shooting some in the back of the head.

But there is fierce debate over whether the law goes too far and supplants the role of parents in deciding which video games are permissible for their kids. And from movie studios to media organizations, lawyers have warned the Supreme Court that regulating video game violence could spill into all forms of artistic expression that depict violence in story lines, whether the movie “Saving Private Ryan” or the “Harry Potter” series. Even the Comic Book Legal Defense Fund has weighed in.

The video game industry insists its voluntary rating system already restricts children from buying violent video games with a “Mature” rating. In fact, the Federal Trade Commission last year found that 80 percent of stores that sell video games refused to sell violent games to minors, better than the movie industry.

“A 13-year-old has a better chance of buying beer at a 7-Eleven than getting a violent video game at a GameStop,” said George Rose, chief public policy officer for Activision Blizzard, the maker of “Call of Duty: Modern Warfare” and other popular games.

Critics, however, say the industry’s rating system has no teeth, serving merely as a guide for parents. James Steyer, head of Common Sense Media, a leading group monitoring media and children, said the California law does not interfere with artistic expression.

“Whose speech is being violated?” asked Steyer, also a Stanford professor. “It’s a sales-to-kids issue.”

In last year’s ruling, the 9th U.S. Circuit Court of Appeals found that regardless of problems with violent video games, California officials did not establish a scientific connection between violent video games and physical and psychological harm to minors.

In the end, some parents believe such laws are irrelevant if they are monitoring the games their children play. But Karen Meredith, the Mountain View mother of a soldier slain in Iraq who waged a public campaign against the latest “Medal of Honor” video game, said the industry remains “too cavalier” about keeping violence from children.

“I don’t know why they can’t put a law like that into effect to protect minors,” she said.

Contact Howard Mintz at 408-286-0236.