Britain's King Charles III speaks during a joint address to Congress in the House Chamber at the U.S. Capitol in Washington on Tuesday. | Bloomberg Britain's King Charles III called on the U.S. to maintain its leadership role in the world and to support NATO and Ukraine, in a remarkably pointed speech for a monarch who urged Americans to resist the pull of isolationism. Charles used his remarks to a joint session of Congress — the first such address by a British monarch in more than three decades — to argue for preserving the alliance between the U.K. and U.S. The king appealed to the shared heritage between the two nations, littering his remarks with references to culture, religion and principles behind America’s decision to declare independence 250 years ago.…