Mr. Trump’s decision to distribute the skit to millions of his followers is the latest presidential disparagement of his British counterpart. In recent weeks, the president has mercilessly mocked Mr. Starmer as cowardly and spineless because of his unwillingness to fully join the fight against Iran. Mr. Trump has repeatedly said that Mr. Starmer is “No Winston Churchill” and chided him for not clearing the way for U.S. jets to use British bases for the initial strikes.