Howdy Sonia! Now we're just one appointment away from discovering a Constitutional right for same sex marriage. Turns out that's the whole reason they wrote the dang thing actually.
And it's American to the core that the people who interpret our Constitution do so with any Constitutional authority. Article III has nothing in it granting the Supremes right of nullification over Exec and Legislative branches. Marshall grabbed that in Marbury v. Madison, and we never looked back.
One of the snags in weilding extra-Constitutional power is there's nothing written down about how exactly you're supposed to enforce your stuff. That makes you the weakest branch of the Federal Government. Yet the Supremes have wrought sweeping cultural change over the past fifty years. How DO they do it? Oh same as many other functionally impotent political entities have managed, since the dawn of recorded history. Shrewd alliances, exploiting fear of the unknown, and being a useful excuse at times.
If a Pres ever said, "They've no authority really, I'm gonna do it anyway" Impeachment proceedings would soon follow. If a Congress ever responded to SCOTUS nullification of some legislation by directing they be ignored? Well no Federal Law can be administered without cooperation from some Fed body that answers to the Pres. He/She would laugh at Congress, and side with the Supremes. The SCOTUS relies on the envy between the two strong branches. Shrewd alliances serve a weak political entity.
If it ever came to where the Nine handed down something so loony, both the strong branches combined forces against SCOTUS? It's the end of the game as we know it. Powerful people in Washington like a set of basic ground rules. Without rules, how on Earth can you cheat? Break the power of the Supremes, there's no third player anymore you can hope to leverage for extra juice at times. It's just a two player game now with rules nobody knows yet. Exploit the fear of the unknown.
The Nine, by virtue of not having to stand for election, have often done work the strong branches found too radioactive to even mess with. They're like treaties were in 18th century Europe at times. Gives you excuse to do what you wanted to do anyway. Other times they're deciding something that's been bleeding your main agenda, so you can focus on your stuff, claiming it's out of your hands. Then later, maybe you can even turn the SCOTUS decision in the face of your indecision to political advantage. Be a useful excuse at times.
That's how the weakest branch keeps power. Because in the odd way things work in this crazy first ever experiment with semi-self governance, nine old people with nothing more than black robes and a pretty office building can rule the strong with the implicit threat of their absence.
One more appointment and I'm hearing wedding bells for Siegfried and Roy.