Republican lawmakers are scratching their heads over President-elect Trump’s ambitions to take over Greenland and the Panama Canal, grand plans the incoming commander in chief put back on the table over the Christmas and New Year’s recess. GOP senators and House members view the prospect of the United States taking over Greenland as particularly outlandish, but they are leery of confronting Trump. The idea of resuming direct U.S. control over the Panama Canal also seems unlikely, but some...