The U.S. had 17 bases in Greenland during the Cold War; I know because I spent time at some of those bases. The bases were all abandoned in the 1980s except for a greatly downsized Thule (now Pituffik Space Base). The U.S. government was welcomed in Greenland to locate bases during WWII, and after, to provide security. We left the bases all behind because the threat isn’t there; moreover, we haven’t made any attempt to reopen them. If President Trump really wants to secure the shipping lanes and provide security in the Arctic, he should repair our two broken-down, 50-year-old ice breakers, or build new ones.