The US Supreme Court left in place a broad liability shield for social media companies for content posted by users, insulating Twitter Inc., Facebook Inc. and Google LLC from claims that they provided assistance to Islamic State terrorists.

Acting in a case involving Google, the court said it wouldn’t rule on efforts to limit the immunity internet companies have enjoyed under a decades-old law known as Section 230. In a related case, the court unanimously tossed out a lawsuit that said social media companies bore responsibility under an anti-terrorism law for a 2017 shooting in an Istanbul nightclub.

The decisions together amount to a triumph for social media platforms, assuaging fears that the tech industry might face a new deluge of lawsuits and remove speech across their platforms. At least for the time being, the outcome means it would take an act of Congress to broadly open social media companies to lawsuits over third-party content.