Do not antagonise one's opponents unnecessarily, a basic principle of diplomacy says. But as the United States faces a trade war with China and various tensions overseas, President Donald Trump's emissaries are increasingly ticking off allied countries and being called to account. The ambassadors are consistent with Donald Trump's blunt-spoken style, his “America First” approach to foreign policy and his attitude toward reporters(REUTERS) Just this week, no fewer than three US envoys scrambled to extricate themselves from diplomatic hot water. Denmark's foreign minister summoned the top US diplomat in the country to answer for reports that at least three people...