The U.S. Supreme Court on Monday announced its first formal code of conduct governing the ethical behavior of its nine justices, bowing to months of outside pressure over revelations of undisclosed luxury trips and hobnobbing with wealthy benefactors.

The new code drew mixed reviews, with some critics noting the apparent absence of any enforcement mechanism. It was adopted after a series of media reports detailing ethics questions surrounding some Supreme Court members, in particular conservative Justice Clarence Thomas, even as Senate Democrats pursued long-shot legislation to mandate an ethics code for the nation's top judicial body.