I'd like to comment on a key aspect of TFan's contension that Supreme Court rulings ipso facto constitute "the law of the land."
It's true that American jurisprudence was influenced by the English common law system. After all, we started out as a bunch of English colonies. To some extent, Colonial America was governed by common law, although you had some theocratic communities which appeal to Biblical law.
But while there's a degree of continuity with the English system, there's also a significant degree of discontinuity. Unlike England, which had no written Constitution (although they do have Magna Carta, as well as the 1689 Declaration of Rights), the founders of the Republic broke with English jurisprudential tradition by having a written Constitution, which is the supreme law of the land. We need to distinguish between Colonial American jurisprudence and Republican American jurisprudence. A written Constitution subordinates all three branches of gov't to a Constitutional rule of law. In the absence of a written Constitution, precedent is more authoritative.
This is reinforced by the fact that the American Republic was founded on the consent of the governed. And even in Colonial America, deference to common law was far from absolute, as Larry Kramer has documented, in his historical investigations of "popular constitutionalism." And that's because there was a dialectical relationship between common law and fundamental law (or natural law).