Interesting thread. I love discussing the Constitution and the rights of U.S. citizens. It is always Very important to know your rights. I am and have been very interested in national and global politics for a while, just recently I finished a Political Science class. Good shit, I recommend it.
While it's true that things are pretty messed up in the bureaucratic systems and we have moved further away from the Constitution, the Constitution itself is vague on most all of today's situations. So in most cases, the Constitution needs to be somewhat interpreted to see how it will apply to that situation. There are many people who are pro-interpretation and many that are die-hard "as it was written" Constitutionalists. What this all boils down to is if there is a case involving subjects that are not explicitly defined in the Constitution, i.e. drugs, what happens is it ends up at the U.S. Supreme Court, where the judges there decide what should/should not be legal according to the Constitution. What they rule in these situations often sets a precedent for future cases, and is usually "assumed" into law.
The Constitution and the Bill of Rights are crystal clear on every major point, but since they're intended to limit centralized authority, and that is seen as unfavorable by federalists, the issues are mucked up until they appear wishy washy.
For example:
Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.
This could hardly be more clear, yet we now have "no free speech zones" that the
Secret
Service can declare on a whim. In Nevada(and elsewhere) "free speech zones" were established for people to protest. This is clearly unconstitutional as the 4th branch of government has no authority to create law. That is the function of Congress and they cannot create a law that infringes freedom of speech.
A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.
...again, this is not ambiguous. It's not until you get a whole bunch of scumbag lawyers in a room redefining words like "people" and "Arms" that things get...flexible.