Th U.S. Constitution
"The accumulation of all powers, legislative, executive, and judiciary, in the same hands... may justly be pronounced the very definition of tyranny."
The Federalist #47, James Madison
It is a pity that when most Americans think of the Constitutional protection of their liberty (to the extent they think of it at all) the Bill of Rights is all that comes to mind. These ten amendments were such because they were an after-thought, and they were opposed by those who argued that explicitly listing protections might imply limitation to them.
The main body of the Constitution contains the main bulwarks against the subversion of liberty with three underlying principles - limited government, separation of powers, and a system of checks and balances. The second of these principles is neatly encapsulated by by our friend "little Jemmy" Madison in the above snippet from The Federalist Papers. The third principle, checks an balances, can be easily be envisioned as a kind of political "rock, paper, scissors" game. Both of these principles should be familiar to any middle school student, but it has become increasingly and alarmingly clear that too many of our leaders and too many of those who continually vote for them, either do not understand them, or particularly in the case of leadership, deliberately ignore them.
The first principle, limited government, is perhaps the least understood. The power of the states in this union is plenary; i.e. each of the states has the power to do anything it pleases, so long as it does not violate the federal Constitution or its own. This is not true with regard to our federal government. All of its powers and all of its actions must be derived from an express provision in the Constitution. This is why we get, for example, arguments about Obamacare and the commerce and taxing clauses, or justifications of the Civil Rights Act by pointing out that even a hot dog vendor gets his mustard and relish shipped across state lines. The Civil Rights Act obviously stretched the commerce clause to achieve a noble purpose, but Obamacare and other recent actions clearly just snap right through these protections, effectively neutering them.
There are those on both the right and the left (though it must be said more so on the left) who view the opposition as not merely misguided but evil, and their own causes so self-evidently just that the opposition must be destroyed - no matter what the means. They should heed the warning given by Sir Thomas More to his son-in-law Roper in A Man For All Seasons:
Roper: So now you'd give the Devil the benefit of law!
More: Yes. What would you do? Cut a great road through the law to get after the Devil?
Roper: I'd cut down every law in England to do that!
More: Oh? And when the last law was down, and the Devil turned 'round on you, where would you hide, Roper, the laws all being flat?... Do you really think you could stand upright in the winds that would blow then? Yes, I'd give the Devil benefit of law, for my own safety's sake.