Trump is obsessed with money -- making it, taking it, and keeping it. The purpose of NATO isn't to equalize budgetary contributions of member states. The purpose is to keep the most powerful countries in the world working in some way in concert with one another, in communication with one another, so that we don't have a repeat of the first half of the twentieth century, when Europe was overrun by two World Wars. Russia would like nothing more than for NATO to dissolve, and Trump seems determined to make their wish come true.