Would it not be simpler and sounder to legislate for maximum terms? Say sixteen years, which allows a (presumably) Democratic president to instantly fill two positions, and move to a 5-4 conservative majority, with a flip to 4-5 by the end of the term. Ditto for the appeals courts. It's silly to allow appeals judges to serve to their dotage, and everybody gets stale in a job after 12 to 15 years.