Historical Documents
And now, some Historical Documents for your reading pleasure:
Declaration of Independence
United States Constitution
Bill of Rights
Additional Amendments to the Constitution
Patrick Henry's "Give me Liberty or Give me Death Speech
I also recommend that you read the Federalist Papers, which you can find here. Specifically, focus on Federalist #29, written by Alexander Hamilton for Second Amendment inspiration. The Anti-Federalist papers are just as important, and can be found here.
Thomas Paine's work was very good, as well. You can find his work "The Crisis" at this link. It is an external website, not affiliated with this one at all. Another well-known Paine work is "Common Sense". Again, I'll direct you to an external website, here.