the limit does not exist
The idea of imposing term limits on Supreme Court justices is quite popular among the electorate — yet that support "isn't catching on among elected officials on Capitol Hill who would be the starting point on any alterations to the makeup of the Supreme Court," reports The Washington Post.
Reasons vary. For some, especially Democrats who have endorsed structural changes to the court, adding term limits would take too long, because it would involve an amendment to the Constitution. Expanding the court via statute is, "a far simpler process than passing an amendment," writes the Post, and would have similar effects.
"It takes years to work through the state legislatures," Sen. Elizabeth Warren (D-Mass.), who is in favor of court expansion, told the Post. "We don't have years when the Supreme Court is gutting voting rights, gutting union rights, gutting the equal protection clause and signaling that it's going to overturn Roe."
For reluctant Republican officials, legal changes to the court seem like part of "a broader effort from Democrats to politicize the judiciary," writes the Post. "I think the system has worked well. I don't see a need to change it," said Sen. Lindsey Graham (R-S.C.). "The reason they're talking about changing it is because, you know, Democrats lost elections, which have consequences."
In general, those in favor of limiting justices' tenures, often to an 18-year term, believe it would ensure the court reflects election outcomes over time and allow for more predictable appointments, while opponents think it would harm justices' ability to remain independent. The U.S. is the world's only major democracy without either a mandatory retirement age or a term limit for those who serve on its highest court.