At least, the Americans should fix their constitution to say that their institutions ain't allowed to spy on any human without proper judical oversight. Otherwise, as you, I don't care about their legal system.
That is actually what the constitution says. The US government should get warrant when spying on anyone regardless of who they are or where they are. The limitations are placed on the government, not the other way around.
It is only by legal convention that the US government does warrantless spying on non US citizens and gets away with it.
It is only by legal convention that the US government does warrantless spying on non US citizens and gets away with it.