Final answer:
Thomas Jefferson's quote refers to the social contract and the right to overthrow a government that fails to protect natural rights, an idea influenced by John Locke and enshrined in the Declaration of Independence.
Step-by-step explanation:
The quote by Thomas Jefferson refers to the concept of a social contract and the associated right of the people to overthrow their government if it fails to protect their inalienable rights. Jefferson, influenced by John Locke's philosophy, believed in natural rights such as life, liberty, and the pursuit of happiness, which were outlined in the Declaration of Independence. If a government fails to secure these rights, the citizens have not only the right but also the duty to overthrow such a government and establish a new one that will ensure their safety and happiness.