Regarding SCOTUS, we have impeachment for misbehavior. That is the only (or should be the only) control put on SCOTUS by another branch of government. If SCOTUS wants to enact a code of ethics for itself, then they should do so.
It is comical to think Congress might impose ethics obligations on SCOTUS such as no trading in stock of a company appearing before them, while Congress reserves the right to insider trade for itself.
Congress does have the power to increase and shrink the court at will, but that is a power that should not be exercised by either party. Once one uses it, the other will, too, and then we no longer have an independent judiciary branch of our government.
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