When you think of a national monument, you probably think of a beautiful statue or some stately structure that honors a former president. They're nice to have, nice to go look at. You probably don't think of a "national monument" as 1.5 million acres of land that contains crucial natural resources the nation needs, but thanks to the national monument designation, can't touch.
Welcome once again to the final days of the Obama presidency, in which the whole point is to take abuse of executive power to new and, Obama homes, irreversible new heights. Screw your neighbors. Screw your own country. You've got nothing to lose at this point, and you think you've come up with a way to do it that leaves your successor helpless to reverse your abuses once you're gone. One day it's drilling in the Atlantic and the Arctic. The next it's the de facto declaration of war against one of your best allies.