It depends on what changes they propose.
Changing the lifetime tenure of Supreme Court Justices would require a constitutional amendment.
But adding justices to the Supreme Court, changing the number of seats on the Supreme Court , would only require an act of Congress.
And I think there is a code of ethics that lower court federal judges are held to. If they want to extend that code of ethics to the Supreme Court I don’t know if that requires legislation, or perhaps action on the part of the court itself to set up ethical standards.
But I don’t think a code of ethics would require a constitutional amendment.
Yes but it would still take impeachment to get rid of a judge should some code of ethics be “violated” according to the flexible goalposts thinking of the democrat party!
https://www.uscourts.gov/judges-judgeships/code-conduct-united-states-judges
Canon 1: A Judge Should Uphold the Integrity and
Independence of the Judiciary
An independent and honorable judiciary is indispensable to justice in our society.
A judge should maintain and enforce high standards of conduct and should personally
observe those standards, so that the integrity and independence of the judiciary may be
preserved. The provisions of this Code should be construed and applied to further that
objective.
Canon 2: A Judge Should Avoid Impropriety and the Appearance
of Impropriety in All Activities
A. Respect for Law. A judge should respect and comply with the law and
should act at all times in a manner that promotes public confidence in the
integrity and impartiality of the judiciary.
B. Outside Influence. A judge should not allow family, social, political,
financial, or other relationships to influence judicial conduct or judgment.
A judge should neither lend the prestige of the judicial office to advance
the private interests of the judge or others nor convey or permit others to
convey the impression that they are in a special position to influence the
judge. A judge should not testify voluntarily as a character witness.
C. Nondiscriminatory Membership. A judge should not hold membership in
any organization that practices invidious discrimination on the basis of
race, sex, religion, or national origin.
more (20 pages total) at:
https://www.uscourts.gov/sites/default/files/code_of_conduct_for_united_states_judges_effective_march_12_2019.pdf