Misquoting historical political figures and documents is common in political debates. Here's a list of original sources to keep your opponent's feet to the fire:
Bill of Rights
The first 10 amendments to the U.S. Constitution, describing the individual rights of Americans.
Constitution of the United States of America
Declaration of Independence
Not intended to be a legal document, it nonetheless voices the principles upon which America was built.
The Federalist Papers
The Federalist arguments in the debate over ratifying the U.S. Constitution.
Locke's "Second Treatise on Government"
An important source of ideas for the U.S. Constitution.
The writings of Thomas Jefferson
Libertarians quote him as their own, but his writings say otherwise.