In a 21st-century revival of the same expansionist spirit, Donald Trump is fixated on annexing Greenland whether America’s Danish allies like it or not. Other presidents have invoked the legacies of George Washington and Abraham Lincoln, but for Trump, Polk is among the list of paragons. He has referred to Polk as a “real-estate guy” who got “a lot of land,” and he hung Polk’s portrait in the Oval Office last year, replacing one of Jefferson.