John Rawls (b. 1921, d. 2002) was an American political philosopher in the liberal tradition. His theory of justice as fairness envisions a society of free citizens holding equal basic rights cooperating within an egalitarian economic system. His account of political liberalism addresses the legitimate use of political power in a democracy, aiming to show how enduring unity may be achieved despite the diversity of worldviews that free institutions allow. His writings on the law of peoples extend these theories to liberal foreign policy, with the goal of imagining how a peaceful and tolerant international order might be possible.