Oh, flat-tax proposals: So simple. So alluring. So problematic. At an Oct. 18 debate, when presented with the uncomfortable fact that the 9% national-sales-tax portion of his vaunted "9-9-9" plan would combine with state sales taxes to increase the price of basic household goods, Herman Cain argued that federal and state levies were unrelated. "This is an example of mixing apples and oranges. The state tax is an apple, we are replacing the current tax code with oranges, so it's not correct to mix apples and oranges," he explained. When Mitt Romney pointed out that people would still be subject to both sales taxes under 9-9-9, Cain repeated the analogy, leading a befuddled Romney to exclaim, "I'm going to be getting a bushel basket that has apples and oranges in it, because I'm going to pay both taxes." Cain still said no, but logic screamed yes.