In cutting joint drills, Trump has given South Korea’s president what he wants. So why is Seoul so uneasy?

Lee Jae Myung has long pushed for stronger homegrown defences, yet Donald Trump’s move has sparked alarm in some quartersAt their first summit, in August last year, the South Korean president, Lee Jae Myung, told Donald Trump: “If you, Mr President, become the peacemaker, then I will assist you as...