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.
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 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.
Declaring the equality of all men did not, however, prevent the United States from continuing the widespread practice of slavery. However, President Abraham Lincoln relied on the Declaration of Independence when making the case that slavery went against the deepest commitments of the American nation. Though he did so throughout the 1850s and into his presidency, the most famous example can be found in the Gettysburg Address:
Four score and seven years ago our fathers brought forth on this continent a new nation, conceived in liberty and dedicated to the proposition that all men are created equal.
When Elizabeth Cady Stanton and others convened in Seneca Falls, New York in July 1848, they drafted and signed a document titled the Declaration of Sentiments. The opening sentence alludes to this phrase:
We hold these truths to be self-evident, that all men and women are created equal.
I have a dream that one day this nation will rise up and live out the true meaning of its creed: 'We hold these truths to be self-evident: that all men are created equal.