Why Democrats must expand the Supreme Court

[Celerity]

33. Article III states that these judges "hold their office during good behavior," which means they have a lifetime

appointment, except under very limited circumstances. Article III judges can be removed from office only through impeachment by the House of Representatives and conviction by the Senate.

https://www.uscourts.gov/about-federal-courts/types-federal-judges

The language about “holding offices during good behaviour” has been interpreted to mean that the only way federal judges can be removed from office is if the House of Representatives impeaches them, and the Senate convicts them, of “treason, bribery, or other high crimes and misdemeanors.” Only fifteen judges have ever been impeached (that is, formally accused by the House of Representatives) and only eight have been convicted and removed from office. For practical purposes, any judge who does not commit a crime (or do something equally bad) has “lifetime tenure” and will stay in office until he or she dies or voluntarily steps down. And, as the provision says, Congress and the President cannot retaliate against judges by cutting their salaries.

https://constitutioncenter.org/the-constitution/articles/article-iii/clauses/45#article-iii-section-one-by-richard-garnett-and-david-strauss

The Rationale Behind Lifetime Appointments

Although the Constitution does not explicitly mandate permanent tenure, the interpretation that its language implies life tenure is far from a new perspective. Alexander Hamilton, during the drafting era, championed lifetime tenure as essential for judicial independence, arguing that the judiciary’s lack of military or financial power made it the least threatening branch. Although Thomas Jefferson later changed his stance, the Federalists continued to support life tenure to safeguard judicial independence. Despite critics’ doubts about whether life tenure truly enhances judicial independence, the prevailing rationale today is that this system “insulates [federal judges] from the temporary passions of the public, and allows them to apply the law with only justice in mind, and not electoral or political concerns.”

https://www.law.georgetown.edu/legal-ethics-journal/blog/lifetime-appointments-of-federal-judges-a-double-edged-sword/

BTW, I am fully on board with term limits, but alas a Constitutional Amendment that puts them in place will never pass, or at least not for decades from now, IMHO.