Investigation by Senate Democrats found that Thomas accepted gifts and travel worth more than $4.75m since 1991

A nearly two-year investigation by Democratic senators of supreme court ethics details more luxury travel by Justice Clarence Thomas and urges Congress to establish a way to enforce a new code of conduct.

Any movement on the issue appears unlikely as Republicans prepare to take control of the Senate in January, underscoring the hurdles in imposing restrictions on a separate branch of government even as public confidence in the court has fallen to record lows.