The decision to try to compel cooperation from a leading judicial activist and a Republican megadonor came over fierce G.O.P. opposition and threats of retaliation.
The code of conduct issued on Monday, following reports of undisclosed travel and gifts, includes no enforcement mechanism and lets individual justices decide ethics questions for themselves.
The Judiciary Committee postponed votes to issue subpoenas for benefactors of Justices Clarence Thomas and Samuel Alito after Republicans threatened a politically charged fight.