It's an issue on whether you believe in a 'living' constitution or if you think it should only be interpreted in light of the intentions of the people who first approved it. If you believe it's the former, then you have to be prepared for your rights and privileges to fluctuate with time (it could go backwards if a dictatorish type person comes up and appoints those types of judges, or forwards if you get a liberal court). If you believe it's the latter, then you have to accept things like the fact that was legally justified that the rights in the constitution not apply to black people (until the reconstruction amendments - 13th, 14th or 15th), or the fact that some people who were involved with the constitution thought that it was treason
to criticize the President.
Frankly, I'm not sure if I want current society to be held to the thoughts and intentions of a bunch of guys from the 18th century (as enlightened as they were).