Most people would agree that domestic politics affect diplomatic negotiations, and last month’s Hanoi summit was interesting because it provided some visible clues as to the relationship between what goes on at home and foreign policy.

U.S. President Donald Trump has said that the congressional hearing of Michael Cohen — which took place during the summit — might have contributed his decision to walk away.

North Korean leader Kim Jong Un, too, seems to have been driven by domestic politics — albeit from the different direction. He sent two kinds of messages as the summit ended, a bitter one