https://www.nytimes.com/2020/09/22/opinion/ginsburg-supreme-court-confirmation.html
Supreme Court justices often try to retire during the presidency of someone sympathetic to their jurisprudence. Of course, that doesn’t always work: Justice Scalia died after almost 30 years on the high court trying to wait out President Barack Obama, and Justice Ginsburg died after nearly 27 years trying to outlast President Trump.
Over all, though, strategic retirements give the justices too much power in picking their own successors, which can lead to a self-perpetuating oligarchy. The current system also creates the impression that the justices are more political actors than judges, which damages the rule of law. It may even change the way the justices view themselves.
No other major democracy in the world gives the justices on its highest court life tenure, and nor do 49 of the 50 states. The longest terms are more like the 12-year terms served by German Constitutional Court justices. Countries and states that do not have term limits have mandatory retirement ages; many jurisdictions have both.
The unpredictable American system of life tenure has led to four presidents picking six or more justices and four presidents selecting none, as happened with Jimmy Carter. This gives some presidents too much influence on the Supreme Court and others too little.