The Catholic University of America


Mark L. Rienzi is an associate professor at The Catholic University of America, Columbus School of Law. Professor Rienzi teaches constitutional law, religious liberty, torts, and evidence. He was voted Teacher of the Year for 2011 and 2012 by the Law School's Student Bar Association.
Professor Rienzi's litigation and research interests focus on the First and Fourteenth Amendments, with an emphasis on free speech and the free exercise of religion. He is currently serving as counsel in several constitutional cases across the country, including a First Amendment challenge to a Massachusetts abortion clinic buffer zone law, a free exercise challenge to an Illinois law that requires all pharmacists to dispense the "morning after" pill, several cases challenging speech regulations directed at pro-life pregnancy centers. 
Professor Rienzi is also Senior Counsel at the Becket Fund for Religious Liberty, a non-profit, non-partisan religious liberties law firm dedicated to protecting the free expression of all religious faiths.  At the Becket Fund, Professor Rienzi is counsel in several challenges to the HHS Mandate.
Professor Rienzi's latest article, The Constitutional Right Not to Kill appeared last year in the Emory Law Journal.  The piece is a follow up to The Constitutional Right to Refuse:  Roe, Casey, and the Fourteenth Amendment Rights of Healthcare Providers, which was the lead article in the Notre Dame Law Review's 2011-2012 volume. 
Professor Rienzi is a widely sought after speaker on constitutional issues, particularly concerning abortion and the First Amendment. Professor Rienzi has been invited to discuss these issues at Harvard Law School, Columbia University Law School, Georgetown University Law Center, Boston College Law School, Notre Dame Law School, the National Press Club, and the Capitol.  His writings on constitutional issues have appeared in The New York Times, Roll Call, U.S. News and World Report, National Review Online, The New York Daily News, The Chicago Sun-Times, and the National Catholic Register.  He has appeared on various television and radio programs, including NBC, ABC, FOXNews, and NPR. 

Prior to joining CUA, Professor Rienzi served as counsel in the Supreme Court and Appellate Practice Group at Wilmer Hale LLP.  Prior to joining Wilmer Hale, he served as law clerk to the Hon. Stephen F. Williams, senior circuit judge for the U.S. Court of Appeals for the D.C. Circuit. Professor Rienzi was an editor of the Harvard Law Review. He earned his J.D. from Harvard Law School and B.A. from Princeton University, both with honors.

Research and Writing

View Professor Rienzi's SSRN author page

In His Words ...

"The law is a tool for structuring society. It is a tool for protecting the weak, the oppressed and the voiceless. It is a tool for protecting freedom. CUA Law students learn how to use that tool, and are inspired to use it for good when they graduate." 

– Mark L. Rienzi


Office: 475 Law School
The Catholic University of America
3600 John McCormack Rd., NE
Washington, D.C. 20064

Phone: 202-319-5140



  • Constitutional Law
  • Religious Liberty
  • Torts
  • Evidence



Harvard Law School J.D. 2000 cum laude  


Princeton University B.A. 1997 cum laude


Areas of Expertise

  • Religious Liberty
  • Free Speech,
  • Abortion
  • Fourteenth Amendment
  • For additional information about our professors' areas of speciality, see the Catholic University Experts page.


  • Senior Counsel at the Becket Fund for Religious Liberty, Washington, D.C.
  • Counsel, Supreme Court and Appellate Practice Group,  Wilmer Hale LLP
  • Judicial clerk, the Hon. Stephen F. Williams, senior circuit judge for the U.S. Court of Appeals for the D.C. Circuit