Tonight's Republican debate in Las Vegas will focus on Herman Cain, who has vaulted from nowhere to lead all GOP hopefuls with 27 percent of the vote nationwide, according to a recent Wall Street Journal poll. More specifically, the moderators will focus on Cain's tax proposal, the 9-9-9 plan, which reduces personal income and corporate income taxes to 9 percent and adds a national sales tax, also at 9 percent. Here are nine questions the moderators should ask:

1) Tax experts have said that, by enacting a 9 percent tax on three levels of income -- on corporate income, personal income, and spending -- you are essentially levying a 27 percent payroll tax without exemptions. Are they wrong?

2) If they're wrong, explain how a family being paid $40,000 out of a corporation's income and spending all $40,000 that year would not ultimately forfeit 27 percent of their income to the government. If they're right, why shouldn't somebody call the tax a 27 percent tax instead of a 9-9-9 tax?