It's easy to scoff at the anti-free-trade rhetoric emanating from the U.S. presidential campaign trail. Donald Trump keeps yelling about China, Mexico and Japan. Bernie Sanders won't stop shouting about greedy multinational corporations. Hillary Clinton, Ted Cruz and John Kasich are awkwardly leaning in the same direction. If you're a typical pro-trade business executive, you're tempted to ask: Were these people throwing Frisbees on the quad during Econ 101?