Blaming pop culture for criminal behavior, as President Trump did by linking "grisly video games" to mass shootings such as those in El Paso, Texas, and Dayton, Ohio, is a centuries-old tactic.

From the Athenian government's execution of the philosopher Socrates for corrupting the minds of the city-state's youth in 399 B.C. to the ban of Mark Twain's classic Huckleberry Finn by Concord, Massachusetts, librarians in 1885, shifts in art, education, and science have been popular targets for governments seeking to assign responsibility for social ills.

In the 1930s, for instance, Hollywood tightened its control over film production in response to complaints from the Women's Temperance Union, which was seeking government regulation, by establishing a code that forbade production of any movie "that would lower the moral standards of those who see it."

The rule, which specified that audience sympathies should never be "thrown to the side of crime, wrongdoing, evil or sin," persisted until a Supreme Court decision in 1959 that extended First Amendment protections to movies, gradually loosening controls through the 1960s.

Similar criticism would later be leveled at television shows, hard rock music, and early versions of video games, said Christopher Ferguson, a Stetson University psychology professor who has studied the effects of violence in media and video games and shared his perspective with the Trump administration's Federal Commission on School Safety last year.

So far, studies haven't found a conclusive link between video games and violent real-world behavior, he said, and those indicating one have been impossible to replicate for verification.

What has happened instead is that "older adults tend to panic about new technology and new media that they don't use and don't understand," he told the Washington Examiner. "They tend to blame it for all kinds of social problems that they worry about."

Since older adults tend to vote more often, those narratives take hold until another generation, more familiar with the technology, becomes politically active and dismisses it as a threat, he said. "There's always this sense that the next media, the next technology is going to be the one that's the problem."

Trump's condemnation of violent games follows similar statements from House Minority Leader Kevin McCarthy and Texas Lt. Gov. Dan Patrick, who cited a manifesto that El Paso authorities have yet to conclusively link to 21-year-old Patrick Crusius, arrested at the packed shopping center after shootings that claimed 22 lives.

The document, posted on social media, described living out a Call of Duty super-soldier fantasy, the lieutenant governor told Fox News on Sunday.

"Look at the common denominators," he said. "We've always had guns. We've always had evil. What's changed where we have this rash of shootings? I see a video game industry that teaches young people to kill."

Just hours after the El Paso slayings, Dayton police shot and killed 24-year-old Connor Betts as he fired into a crowd of late-night revelers in the city's Oregon district, leaving nine of them dead.

"We must stop the glorification of violence in our society," Trump said in a speech from the White House a day later. "This includes the gruesome and grisly video games that are now commonplace. It is too easy today for troubled youth to surround themselves with a culture that celebrates violence. We must stop or substantially reduce this, and it has to begin immediately."

The president expressed similar concerns after a shooting spree at a south Florida high school in early 2018 that killed 17 students and staff members. While the school safety commission he formed afterward found depictions of violence in 90% of movies, 68% of video games and 60% of TV shows, its December 2018 report noted that studies haven't conclusively linked such media with physical aggression.

Ultimately, the report judged parents as best equipped to determine which TV shows their children watch and what video games they can play. Rating systems such as those developed by the Entertainment Software Ratings Board can help, it suggested.

The Entertainment Software Association, a trade group representing the $43 billion industry, agreed with that recommendation while rejecting any claim that its products cause violent behavior.

"More than 165 million Americans enjoy video games, and billions of people play video games worldwide," said Kara Kelber, a spokeswoman for the association. "Yet other societies, where video games are played as avidly, do not content with the tragic levels of violence that occur in the U.S."

Tighter federal restrictions on the industry and its products are unlikely for now, with Democrats in control of the House while Republicans hold the Senate and the White House.

Any legislation passed later would still have to overcome the protective barrier provided by the Supreme Court's 2011 decision striking down a California law that restricted the sale of violent video games to minors.

"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," then-Justice Antonin Scalia wrote in the 7-2 decision.

"Whatever the challenges of applying the Constitution to ever-advancing technology, 'the basic principles of freedom of speech and the press, like the First Amendment's command, do not vary' when a new and different medium for communication appears," Scalia wrote in the opinion, in which he was joined by Chief Justice John Roberts and conservative Justice Samuel Alito.

"No doubt a state possesses legitimate interest in protecting children from harm," Scalia said, "but that does not include a free-floating power to restrict the ideas to which children may be exposed."