Tthe Wall Street Journal’s Steve Moore, who helped design Herman Cain’s 9-9-9 tax plan, is having second thoughts about the political viability of the national sales tax aspect of the plan and has recommended a 9 percent payroll tax to replace it. In an interview with National Review Online, Moore explains that he has “come to the conclusion that a national sales tax is just a nonstarter,” politically. While he wasn’t expecting such a hostile reaction to the idea, Moore concedes that “people are naturally suspicious of a new tax.” Cain’s current plan would eliminate the payroll tax altogether, and...