King Charles III delivered an historic speech to a joint session of Congress on Tuesday, April 28, 2026. During his address, he cited an article by Catholic Law's Professor Derek Webb, published in 2018 in the Journal of Supreme Court History, in a line that drew a bipartisan standing ovation from high-ranking American officials, British dignitaries, and special guests.

In that article, “What Say the Reeds at Runnymede? Magna Carta in Supreme Court History,” Webb identified 160 distinct Supreme Court cases in which the Court had cited Magna Carta since 1789. And Webb charted and organized all those citations to show all the diverse ways in which the Great Charter has been used to support and inform various legal claims over more than 200 years. 

As King Charles III put it, “The U.S. Supreme Court Historical Society has calculated that Magna Carta is cited in at least 160 Supreme Court cases since 1789, not least as the foundation of the principle that executive power is subject to checks and balances.”

At the state dinner later that evening at the White House, President Trump joked: “I want to congratulate Charles on having made a fantastic speech today at Congress… He got the Democrats to stand, and I've never been able to do so. I couldn't believe it …”

This is only the second time a British monarch has addressed a joint session of Congress. Queen Elizabeth II was the first to do so in 1991. As Prime Minister, Winston Churchill addressed a joint session of Congress three times, the first in 1941 just weeks after the attack on Pearl Harbor.

Professor Webb says that the citation by the King before the joint session was an extraordinary and completely unexpected honor. “As it happens, I was actually in the field at Runnymede, England for the celebration of the 800th anniversary of Magna Carta back in 2015, when I was working on that article as a Supreme Court Fellow. And I was thrilled to see Queen Elizabeth there that day drive by in her motorcade. To have her son, now King Charles, make reference to that article years later was very special and an enormous honor.”