Remember when Barack Obama promised the world in 2008, only to leave some enthusiasts bereft after he failed to close Guantanamo, much less slow the rise of the oceans? If we elect a President Donald Trump, you ain't seen nothing yet when it comes to disillusionment. Imagine the fury among his supporters when their outsized hero is exposed as a huckster who cashes the check as soon as the car is off the lot. The brash billionaire has sold I-can-fix-it-just-you-watch pledges to millions of voters enraged about a steady stream of hollow political promises. To them, Trump towers as the...