King Charles received a standing ovation as he delivered a historic address to Congress in Washington, praising the 'indispensable' partnership between the United Kingdom and the United States. Speaking in the Capitol, he warned that the two nations must stand together in a 'more volatile, more dangerous' era marked by conflict in Europe and the Middle East. Lawmakers repeatedly interrupted his speech with applause, underscoring the symbolic weight of the visit amid recent political tensions.

The King called for continued support for the North Atlantic Treaty Organization and for the defence of Ukraine, while highlighting Britain’s commitment to a major increase in defence spending. Emphasising shared democratic values and the rule of law, he urged both countries to resist isolationism and uphold their long-standing alliance. He also condemned political violence following a recent attack in Washington, declaring that such acts 'will never succeed'.

Blending moral reflection with diplomacy, the monarch spoke of faith, mutual respect among religions and the enduring strength of democratic traditions. Framing the relationship as a 'story of reconciliation, renewal and remarkable partnership', he left to loud cheers, in what was seen as a significant effort to reinforce transatlantic ties during a period of uncertainty.