One could also argue that those very same words help make the constitution a living document that defines the spirit of the law far above simply the letter of the law.
Years of precedent in the form of case law do also weigh in, as others have mentioned.
if US judges took the same "living tree" approach to the constitution that Canadian judges do to theirs, I'd agree with you, but since they instead try and discover "original intent" I think it just unnecessarily introduces confusion over what, exactly, the original intent is/was, which allows for people, governments, and organizations to abuse both the spirit and the letter of it.
Frankly, anytime there is any interpretation by a human involved... wait, no, anytime there is a human involved, period, there is the opportunity for abuse of the system.
entirely true, but some things are easier to abuse than others, just like how every computer is theoretically hackable, but some are easier to hack than others.
Years of precedent in the form of case law do also weigh in, as others have mentioned.