Polar War: Submarines, Spies, and the Struggle for Power in a Melting Arctic, by Kenneth R. Rosen, Simon & Schuster, 320 pages, $29
When he first started talking about it, President Donald Trump's desire to take over Greenland sounded like a joke. Now European leaders are taking the possibility of a hostile takeover—and possibly even a war for the Danish Arctic island—as a deadly serious threat. After Trump's diet regime change operation in Venezuela, he immediately set his sights on Greenland, with the implication that it would be an armed conquest rather than a voluntary purchase.
