28 USC 455:
(a) Any justice, judge, or magistrate judge of the United States shall disqualify himself in any proceeding in which his impartiality might reasonably be questioned.
“It is clear beyond any doubt that Justices Kagan and Ginsberg have held exceedingly strong opinions that same-sex marriages were constitutional by virtue of their having performed them. When Justices of the highest court in the country believe they do not have to comply with essential laws governing courts themselves, then there is no overriding legitimate law of the land, which action standing alone is enough to substantiate tyranny.”
Source: Gohmert on Supreme Court Ruling of Same-Sex Marriage – Rep. Louis Gohmert (R-TX)