“The invasion of private rights is chiefly to be apprehended, not from acts of Government contrary to the sense of its constituents, but from acts in which the Government is the mere instrument of the major number of the Constituents.” –James Madison, letter to Thomas Jefferson, 1788

You may read this letter from the Father of the Constitution, Madison, to Jefferson, on the importance of the Bill of Rights, here:

http://www.constitution.org/jm/17881017_bor.htm