The Trump administration pressed its offensive against online companies it accuses of censoring conservatives, asking regulators to dilute a decades-old law that social media giants such as Facebook Inc., Twitter Inc. and Google say is crucial to them.

The Commerce Department on Monday asked the Federal Communications Commission to write a regulation weakening protections laid out in Section 230, language in a 1996 law that protects online companies from legal liability for users’ posts, and for decisions to remove material.

The request was called for in an executive order that U.S. President Donald Trump signed in May. Tech trade groups, civil liberties organizations and legal scholars have slammed the executive order, saying that it was unlikely to survive a court challenge.