Hadley P. Arkes (born 1940) is an American political scientist and the Edward N. Ney Professor of Jurisprudence and American Institutions emeritus at Amherst College, where he has taught since 1966. He is currently the founder and director of the James Wilson Institute on Natural Rights & the American Founding in Washington, D.C.
In a series of books and articles dating from the mid-1980s, Arkes has written on a priori moral principles and advocated for their impact on constitutional interpretation. He has also dealt with their relation to constitutional jurisprudence and natural law, and their challenge to moral relativism. His works draw on political philosophers from Aristotle through the U.S. Founding Fathers, Lincoln, and contemporary authors and jurists.
John O. McGinnis, reviewing Arkes' Constitutional Illusions & Anchoring Truths in The Wall Street Journal, writes that it tries to find a path between the extremes of originalism, where the meaning of the U. S.Constitution is fixed by its original text, and the idea of the living constitution, where its meaning is updated by evolving moral principles.
Arkes is founder and a member of the Committee for the American Founding, a group of Amherst alumni and students seeking to preserve the doctrines of "natural rights" exposited by some American Founders and Lincoln through the Colloquium on the American Founding at Amherst and in Washington, D.C.
In 2010 Arkes, born and raised a Jew, converted to Catholicism, which he described as a fulfillment of his Jewish faith.
In September 2016, Arkes was among 125 Conservatives for Trump who announced they supported Donald Trump's candidacy to be president.
- Bureaucracy, regime and presumption : the national interests on the Marshall Plan (dissertation: University of Chicago, 1967).
- The philosopher in the city (Princeton University Press, 1981).
- First things: an inquiry into the first principles of morals and justice (Princeton University Press, 1986).
- On natural rights : speaking prose all our lives (Heritage Foundation, 1992).
- A jurisprudence of natural rights : how an earlier generation of judges did it (Heritage Foundation, 1992).
- Beyond the Constitution (Princeton University Press, 1992).
- The Return of George Sutherland: Restoring a Jurisprudence of Natural Rights (Princeton University Press, 1997).
- The mission of the military and the question of "the regime" (Colorado Springs, CO: United States Air Force Academy, 1997).
- Natural rights and the right to choose (Cambridge University Press, 2002).
- Constitutional illusions and anchoring truths : the touchstone of the natural law (Cambridge University Press, 2010).
- Hadley Arkes, 1995. "Strauss and the Religion of Reason," National Review, 47(12), June 26, pp. pp. 60–63. Accessed 08-28-10.
- "When Justice Comes Naturally". Wall Street Journal. August 27, 2010.
- Committee for the American Founding, Amherst College.
- Hadley Arkes, Senior Fellow,", Ethics and Public Policy Center.
- Christine M. Williams (2010).  "Pro-Life Leader Hadley Arkes Becomes Catholic," The Anchor," Diocese of Fall River. May 10. Accessed 08-28-10.