King Charles III warns against isolationism, reaffirms NATO commitment in US Congress address

King Charles III used a landmark address to the United States Congress to caution against rising isolationism and underscore the enduring importance of NATO and transatlantic unity, during his first state visit as monarch alongside Camilla.

Speaking at a joint session of Congress at the U.S. Capitol, the King described the UK-US relationship as a historic alliance built on shared democratic values, saying both nations remain “united in our commitment to uphold democracy, to protect all our people from harm, and to salute the courage of those who daily risk their lives in the service of our countries.”
“I would like to take this opportunity to express my particular gratitude to you all for the great honour of addressing this Joint Meeting of Congress and, on behalf of The Queen and myself, to thank the American people for welcoming us to the United States to mark this semi-quincentennial year of the Declaration of Independence.
“Our destinies as Nations have been interlinked. As Oscar Wilde said, We have really everything in common with America nowadays except, of course, language!”
The nearly 30-minute speech, delivered on the second day of the royal couple’s four-day visit, came at a time of global instability, with ongoing conflicts in Europe and the Middle East. Charles warned that such challenges require nations to work together rather than turn inward, urging continued international cooperation and rejecting isolationist approaches.

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He also reiterated strong support for Ukraine and emphasized the need for a “just and lasting peace,” while highlighting NATO’s role in collective security. The King noted that allied defence cooperation has been central to maintaining stability since the Second World War and remains vital in the current geopolitical climate.
However, the address also revealed visible political divides within the chamber. Democratic lawmakers largely offered standing ovations, particularly on NATO and environmental themes, while many Republicans appeared more reserved. Conversely, when Charles spoke about his Christian faith, GOP members responded with stronger applause than their Democratic counterparts.

Without directly addressing partisan disputes, the King focused on shared history and institutions, referencing centuries of legal and democratic tradition linking the two nations, from Magna Carta to the U.S. Constitution. He also highlighted growing cooperation in defence, trade, and emerging technologies, including artificial intelligence and nuclear innovation.
Charles further warned of environmental degradation, describing the “collapse of critical natural systems” as a global threat requiring urgent action, and called for greater stewardship of nature.

Concluding his remarks, the King urged both nations to strengthen their partnership for the next 250 years, stating that the relationship between the United Kingdom and the United States remains “one of the most consequential alliances in human history.”
“Let our two countries rededicate ourselves to each other in the selfless service of our peoples and of all the peoples of the world,” he said.