You do if you do not want to be removed from the bench. Judges who make explicit statements that indicate they cannot be impartial in a case currently before t

You do if you do not want to be removed from the bench. Judges who make explicit statements that indicate they cannot be impartial in a case currently before them but who do not remove themselves from such cases usually find themselves disrobed and disbarred for violating their ethical duties of impartiality. (UK standards are different from US standards, but the duty of impartiality is generally the same.) Saying that the US is "the enemy" is pretty much as close as you can get to revealing an inability to be impartial.