Finding the Constitution
In Mr. Willis of Ohio, Toby bemoans the fact that his staff has a hard time figuring out how to get a copy of the Constitution, but a printed copy can be a little hard to find. Toby suggested that they look on Amazon.com, which does actually stock a very attractive copy of the Constitution from Applewood Books (ISBN 1557091056). This edition of the Constitution was used in Twenty-Five by Leo to impress upon Charlie the importance of clearing the President's desk (because he was about to temporarily resign under the Twenty-Fifth Amendment.
Viewing the original
An electronic copy of the Constitution is a little easier to find. In Mr. Willis of Ohio, Toby also suggested breaking the glass in the National Archives, which is not necessary to read their copy: it's posted at the National Archives Experience web site.
You can also find a text-only copy at the Legal Information Instutite at the Cornell University Law School.