The opening of the Declaration of Independence written by Thomas Jefferson in 1776, states as follows:

“ We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty, and the Pursuit of Happiness. ”

The same sentiment appears in the Massachusetts Constitution of 1780, which predates the U.S. Constitution by seven years, and was the first of its kind in the world.

“ Article I. All men are born free and equal, and have certain natural, essential, and unalienable rights; among which may be reckoned the right of enjoying and defending their lives and liberties; that of acquiring, possessing, and protecting property; in fine, that of seeking and obtaining their safety and happiness. ”

The year 1780 also marks the first time in America that such wording was used to successfully argue against slavery in a court of law: Brom and Bett vs. Ashley.

Some[who?] feel these statements illustrate the idea of natural rights, a philosophical concept of the Enlightenment; many of the ideas in the Declaration were borrowed from the English liberal political philosopher John Locke. Locke, however, referred to "life, liberty and Property" rather than the pursuit of happiness.

The phrase has since been considered a hallmark statement in democratic constitutions and similar human rights instruments, many of which have adopted the phrase or variants thereof.