In 1848, British Foreign Secretary Lord Palmerston famously said, "We have no eternal allies and we have no perpetual friends … [only] our interests are eternal and perpetual." Similarly, Donald Trump's supporters argue that the billionaire businessman is simply a foreign policy realist taking a cold, hard look at the geopolitical facts -- much as Stratfor tries to do -- and consistently putting American interests first. Realism, though, is not simply a matter of being unsentimental. It is about knowing when an appeal to tradition, values and loyalty will advance a nation's interests and when it will not....