Their separate constitutional court didn't come along until the 20th century[1]. They have 14 justices on that court, but only a maximum of 9 will ever hear a case for precedent-setting decisions, and usually fewer than that (making court packing difficult if not completely pointless).
They have always done what the US should do: keep the votes on a judgment private, so opinions speak for the court as a whole, and they don't let the losers have a soapbox by publishing dissents.
As a cherry on top, they enforce a mandatory retirement age of 70.
These factors make their court an actually apolitical body in a way that's in hilariously stark contrat to the US court. The US court is what you'd make if your entire goal was to turn all its judgments into political theatre.
[1] https://en.wikipedia.org/wiki/Constitutional_Court_(Austria)