@Always Eleven to him,
well that idea,
Quote: Do you think that the phrase "pursuit of happiness" means something different today than it meant in 1776?
is akin to a form of temporal syncretism, where "pursuit of happiness" changes as the culture changes. So it is more than likely any pursuit towards happiness in an 18th century agrarian society would not be the same as a pursuit towards happiness in a post industrial society of the 21st century.
jumping off to a discussion on this ought to start with terms such as freedom and liberty because both terms lie at the heart of the philosophical battles of the Enlightment.
So what did freedom and liberty mean in America 220 years ago during the Constitutional Convention and what do they mean now?
The original poster did a nice connection between the spirit of the Declaration of Independence and the US Constitition; actually the best connection between them I have ever seen.
http://en.wikipedia.org/wiki/Syncretism