It’s not often that Europe speaks with one voice – or responds with such urgency.But US President Donald Trump’s announcement Saturday of sanctions against several European countries that reject any US claim to Greenland, a Danish territory, was one of those moments.EU ambassadors are holding an emergency meeting in Brussels on Sunday in response to Trump’s threat, which he made after an estimated quarter of the population of Greenland’s capital Nuuk joined protests against any potential annexation.Across the continent, among allies that usually tread carefully in responding to utterances from the White House, the response was immediate and emphatic, and...