"A "place holder" until the day that Hillary (bite my tongue) gets to choose her successor?"
I don't think she will be out that quickly, but I expect she will be replaced within 15 years, whichever party is in power.
I don't see the logic of putting in a "placeholder" unless one is sure that the President who gets to choose her successor would be of the same political philosophy. Why relinguish the right to put in a conservative who will serve for 30 or more years?