It’s a commonplace to say that while some provisions of the Constitution may employe diffuse standards (“due process of law”), there are others that are perfectly crisp and rule-like. The age requirements, for example:
No person shall be a Senator who shall not have attained to the Age of thirty Years …
Simple enough, right? There’s no ambiguity about the content of “attained to the age of thirty Years,” is there? There is.
Take a fifteen-year-old, toss her in a spaceship, accelerate it to a relativistic speed with a Lorentz factor of 2, and let it cruise outwards for ten of our Earth years. Turn the ship around and bring it home at the same speed. When our returning astronaut steps down the gangplank, twenty years will have elapsed in the Earth’s reference frame; it will be thirty-five years after her birth. But from her perspective, only ten years of subjective time will have elapsed; she was born twenty-five years ago. Has she “attained to the age of thirty Years?” Good question.
The difference between “due process of law” and “thirty Years,” then, is merely one of degree. If you think that any text is perfectly free from ambiguity, it’s only because you haven’t thrown a hard enough hypothetical at it.