The phrase "When tyranny becomes law, rebellion becomes duty" is widely attributed to Thomas Jefferson, but there is no solid evidence that he actually said or wrote these exact words. The quote expresses the idea that when a government becomes oppressive and unjust (tyrannical), it becomes the responsibility (duty) of the people to resist or rebel against that government. The concept aligns with Jefferson's beliefs and the philosophy of social contract theorists like John Locke, who argued that people consent to be governed but have the right to revolt if the government violates their rights or acts against their interests. Jefferson and the American Revolutionaries believed in the right, and some even the duty, to overthrow a government that abuses its power. Despite its popular association with Jefferson, the phrase itself does not appear in any of his writings and may have originated later, reflecting the spirit of resistance prevalent in his time rather than being a direct quote. It captures a foundational idea in political philosophy about the right and duty to oppose tyranny.