China, Russia, and Iran had to be alarmed by the display of US power in the Venezuela incursion — but so did Denmark, a NATO ally of the United States. In the aftermath of the snatch-and-grab of Nicholás Maduro, President Donald Trump spoke to The Atlantic about his other foreign-policy priorities: "We do need Greenland, absolutely." It might have been easy not too long ago to dismiss this as bluster. Not anymore — not after the successful strikes on the Iran nuclear program and the Venezuela operation...