WASHINGTON — U.S. President Donald Trump's decision to scale back joint military exercises with South Korea does not just slight a longtime ally but raises broader concerns about the security interests of the United States in Asia and elsewhere. Trump explained his decision by citing South Korea’s refusal to join his war against Iran and pointing to what he said was his good relationship with North Korea’s reclusive dictator, a transactional and personal approach to foreign policy that has defined the Republican’s presidency. “There is no American interest that I can see in this,” said Dan Fried, an assistant secretary of state for European affairs in the George W. Bush administration. “On all levels it makes no sense. It undermines the South Koreans, undermines the Japanese, frightens the Taiwanese, unnerves NATO and emboldens the Chinese, not to mention the North Koreans.” Danny Russel, former assistant secretary of state for East Asia and the Pacific in the Obama administration, said Trump's decision to side with North Korea, which strongly objects to the annual joint