Seems to me Jefferson is often misquoted in this regard: He is saying that no law, including the Constitution, is built to withstand the passage of time, and that every twenty years the laws should be revised for current needs. It has been said that he once considered setting expiration dates on all laws--which may well have been a good thing, but far too time-consuming. Guncultists and anarchists do love to think this quote is a license to advocate the overthrow of the government by force, but they're wrong. Jefferson had been through one war of revolution, I can't imagine he'd want another.