Can the Supreme Court reach any conclusion it wants to on any matter or are they bound to respect precedents? Can they reach a decision one day and completely reverse themselves the next? Or, more probably, reach a decision one year and after a few justices are replaced, completely reverse their position a couple of years later?
As a corollary question, what decisions have been totally reversed?
There is a great quote in Lois McMaster Bujold’s SF novel Diplomatic Immunity, where the protagonist is an “Imperial Auditor,” a sort of Internal Affairs special prosecutor/investigator fo5r his government. Asked whether he doesn’t have to get a search warrant, he responds, “I don’t ask for search warrants; I issue them.”
Likewise, SCOTUS does not follow precedent, but makes it. In general, they do follow the principle of stare decisis – “let it stand decided” – if necessary, distinguishing the circumstances surrounding a given case from the case raised as precedent. Suppose, for example, that precedent from case X says that a car validly stopped by a patrol on the highway may be searched without a warrant, e.g., when there are reasonable grounds to suspect the operator or a passenger of holding illegal drugs. If a report indicates that a white Camry left the vicinity of where a guitar and amplifier were reported stolen, it does not therefore follow that the officer may search the glove compartment of a white Camry stopped pursuant to that report – since one cannot secrete a guitar and amplifier in a glove compartment, and that was the probable cause for stopping and searching the car. (This is made up by way of example, but parallels an actual set of such cases.)
When, however, they feel that a pervious precedent was improperly decided, they will reverse the holding of the previous case, setting a new precedent.
So, the extent of the holding is that the Court determines that public education cannot be allowed to provide “separate but equal” facilities, which Plessy had allowed in the case of rail transportation.