Q132. "I have a friend who is taking an American Government course presently. The professor told the class this past week that the U.S. Constitution was plagiarized completely. Is there any validity to this charge?"
A. The Constitution was written by some of the same people who wrote some of the constitutions of the various states, and it makes some sense that they would pull pieces of those that were usable. Many of the framers were also members of Congress and had access to many of the documents that Congress produced, allowed them to draw from them as well. Plagiarized is a strong word today, with negative connotations.
According to The Declaration of Independence and The Constitution of the United States by Pauline Maier, Jefferson's Declaration of Independence was largely based on prior works, specifically Virginia's revolutionary constitution and the Virginia Virginia Declaration of Rights. Jefferson has worked on the former and George Mason on the latter. According to Maier, this use of existing material was entirely within the ethical standards of the day, and, in fact, encouraged. It is little wonder that parts of the new Constitution would similarly be based on prior work.
I think the simpler, and closer to the truth, thing to say is that parts of the Constitution were based on other governmental documents familiar to the framers.