In theory, the law is the law.
But that theory ignores little realities like that you can write down on a piece of paper a rule like, “You must say ‘Hello’ to everyone you meet.” And if you put that rule in front of 1000 humans, a couple of them will deny that you have to say “Hello” to everyone you meet, and explain to you how the rule on the page leads to that ruling. If you look back through GD, you’ll be able to find some genuine nutballs who will give as plainly bizarre readings as that.
Back during the post-9/11 era, the attorney general interpreted the law so that torture was legal rather than being a crime against humanity. After a couple of years, the Supreme Court ruled that this interpretation was stupid and wrong. But, until that point, for a few years, torture was legal. And the basis of illegality, after the Supreme Court decision, was that the attorney general interpreted the SC decision as nullifying his interpretation.
Today, the Federal laws are based on the interpretation of the law, as given by the US Attorney General Bill Barr.
Bill Barr can interpret the law just as widely as we could ever imagine. He could interpret it to mean that the sky is purple, not blue, and if the SC goes against him he could agree with them but then offer a new interpretation saying that the sky is chartreuse and this will have to be fought all of the way to the Supreme Court again because it’s a different argument from before and the judicial branch has to give deference to the Executive and presume faithful intent; or, he could simply interpret their ruling as an agreement with his interpretation, despite the plain text saying otherwise. All of the FBI and attorney generals, ultimately, obey the US Attorney General and follow his instruction not the Supreme Court.
In theory, there are protections against this sort of silly and horrifying sort of activity. The Senate approves the Attorney General, they can impeach him, and the President can fire him.
But there’s zero ambiguity about the matter that torture is a national and global crime, onto which the US is a signatory. And yet, we only ever debated whether it was moral and everyone - including here on the board - largely ignored the fact that the government had simply interpreted the law away and that there was never anything like a penalty for that nor did we do anything to prevent that sort of thing from happening again.
For every subpoena, the executive branch simply has to switch to a new argument and force it to go through the entire depth of the court system to get slapped down.
If they run out of creativity, they can simply interpret the SC ruling in their favor.