President-elect Donald Trump told residents of Greenland that “we’re going to treat you well” as his oldest son visited the mineral-rich Danish territory that’s home to a large U.S. military base, heightening speculation that the incoming U.S. administration could seek to acquire it. The president-elect later told a news conference he wouldn’t rule out using military force or economic coercion to take control of Greenland, saying that “we need it for national security...