In the Declaration of Independence, Jefferson outlined his thoughts on democracy and the rights of people. In the most famous section of the piece, Jefferson proclaims that all men are created equal and have certain rights that cannot be taken away by any government. These rights include the right to life, liberty, and the pursuit of happiness. The Declaration of Independence became the foundation for the Constitution of the United States, as well as for many other democratic constitutions in Europe and around the world.

In the first draft of the Declaration of Independence, Jefferson included a critique of slavery and called for the abolition of the institution — even though he owned slaves himself. His colleagues convinced him to drop the section, because they feared that the southern colonies would object to it and refuse to ratify the declaration. Grudgingly, Jefferson consented. As president, Jefferson later outlawed the importation of new slaves into the United States.