American consumers will feel the pinch from the Iran conflict even if stocks and the dollar don't, one market guru says. Derek Horstmeyer, a finance professor at George Mason University's Costello College of Business, says it's striking how the S&P 500 and the greenback have responded to a major military engagement. It's "hard to believe that you could start a war" that sparks the closure of the Strait of Hormuz — shutting off 20% of the global oil supply and spiking crude prices to over $100 a