Another factor is that the social-media defendants can’t claim that their products were deliberately misused, a key defense that torpedoed the largely unsuccessful public-nuisance lawsuits against gunmakers.

Citing the gun cases, Deborah Hensler, a professor at Stanford Law School, said that “there have been some successes with public-nuisance theory … but there have also been failures, so suits based on public nuisance are by no means a sure thing.”

The social-media cases do face a number of hurdles. The claims “raise very significant First Amendment issues,” said Robert Rabin, another Stanford law professor. “None of the earlier mass-tort actions faced that particular (and substantial) barrier,” he pointed out in an email (parentheses in original).

Politics is an issue here, said Hensler. Among business groups, there’s a lot of opposition to mass torts in general, and it can be easy for local press to castigate such suits as being promoted by “greedy plaintiffs’ attorneys,” she noted. These cases involve “powerful well-resourced corporate defendants,” she added.

One issue is whether public entities other than school districts will be able to join the litigation because they might have trouble proving that they were financially harmed, Hensler noted.