South Korean President, Moon Jae-in, who brokered the talks process between Donald Trump and the North’s leader Kim Jong Un, on Thursday congratulated Joe Biden on his inauguration as US president, tweeting: “America is back.” The relationship between treaty allies Seoul and Washington was at times deeply strained under Trump, who repeatedly excoriated the South for not paying enough towards the US troop presence in the country, demanding billions of dollars more. In his first year in power, Trump raised widespread alarm in the South by engaging in personal insults and...