Presidential appointment of the Chief Justice of the United States to the Commission on the Bicentennial of the Constitution is consistent with the Appointments Clause, art. II, § 2, cl. 2, and, as applied to the unique circumstances of this Commission, with general separation of powers principles.
In addition, participation of the Chief Justice on the Commission would appear to be permissible under the Code of Judicial Conduct.
Members of Congress may participate on the Commission without violating the Appointments Clause or the Incompatibility Clause, art. I, § 6, cl. 2, if the Commission creates an executive committee to discharge the purely executive functions of the Commission, or if the noncongressional members determine that the Commission will not act unless a full majority, including the congressional members, approve.