The United States Supreme Court Fellows Program is currently accepting applications for mid-career professionals interested in pursuing a one-year fellowship at the Court.
Though some Fellows are and have been lawyers, a law degree is not required for the position. Fellows are posted with one of four agencies (the Office of the Counselor, the Sentencing Commission, the Federal Judicial Center and the Administrative Office), each of which could involve some international components, depending on the interest and expertise of the Fellow in question.
A number of internationalists, including those specializing in both public and private international law, have won fellowships in past years. (Current Fellows list is here.)
The application process is open until November 30, 2012.