“Viewed against the backdrop of that law, Mexico’s complaint does not plausibly allege that the defendant manufacturers aided and abetted gun dealers’ unlawful sales of firearms to Mexican traffickers,” Kagan wrote.

Kagan wrote that Mexico made a “general accusation” and did not pinpoint specific criminal transactions in which the gunmakers assisted, creating a high bar to show its lawsuit targeted activity that fell within the PLCAA’s exception for liability. The high court found Mexico did not meet that high bar and ruled the gunmakers enjoy the immunity provided by the PLCAA.

“All of that means PLCAA prevents Mexico’s suit from going forward. The kinds of allegations Mexico makes cannot satisfy the demands of the statute’s predicate exception. That exception permits a suit to be brought against a gun manufacturer that has aided and abetted a firearms violation (and in so doing proximately caused the plaintiff ’s harm),” Kagan wrote.

When the case was argued in March, the justices appeared likely to reject Mexico’s lawsuit. Justice Brett Kavanaugh expressed concern during the arguments that siding with Mexico could expand companies’ liability in other industries.

Justices Clarence Thomas and Ketanji Brown Jackson wrote separate concurrences for the case.

Thomas argued the high court should evaluate the meaning of “violation” under the PLCAA in future cases.

“Particularly given the PLCAA’s aim of protecting gun manufacturers from litigation, see §7901, this issue warrants careful consideration,” Thomas said.

Jackson used her concurrence to agree with the majority opinion while also offering her view that Mexico’s lawsuit was flawed, writing about the lawsuit’s failure to allege “any nonconclusory statutory violations.” She explained the lawsuit is exactly the kind of legal action the PLCAA was passed to prevent.

“Devoid of nonconclusory allegations about particular statutory violations, Mexico’s lawsuit seeks to turn the courts into common-law regulators,” Jackson wrote in her concurrence. “But Congress passed PLCAA to preserve the primacy of the political branches—both state and federal—in deciding which duties to impose on the firearms industry.”

“Construing PLCAA’s predicate exception to authorize lawsuits like the one Mexico filed here would distort that basic design,” Jackson concluded.

TOP CASES THE SUPREME COURT WILL DECIDE AT THE END OF THIS TERM

Matthew Forys, executive vice president of the Landmark Legal Foundation, which defended the gun manufacturers, heralded the decision as a victory for “American business and individual rights” in a statement Thursday.

“Seeking billions of dollars, Mexico’s lawsuit would effectively eliminate the protections for American gun manufacturers that Congress passed in 2005,” Forys said. “Justice Kagan’s unanimous opinion highlights the magnitude of Mexico’s request and the sparse evidence used to justify it. Mexico failed to specify even one specific criminal transaction that the American companies allegedly assisted.”