The firms say their First Amendment rights are being violated when cities and states sue and accuse them of spreading misinformation about climate change.

Oil companies are employing an unusual tactic in some of their biggest court battles. They’re alleging that their critics are infringing on their free-speech rights, invoking laws designed to protect people who challenge the powerful.

The laws, known as “anti-SLAPP” provisions, were created to stop companies or people from silencing their critics with the threat of costly lawsuits. Oil companies have turned this around, arguing that climate lawsuits against them should be thrown out because they infringe on the companies’ protections under the First Amendment.

“What we’re seeing now is a complete inversion” of the original intent of these laws, said Nicole Ligon, an assistant professor of law at Campbell University in North Carolina and expert on freedom of speech and SLAPP, which is shorthand for strategic lawsuit against