Although this disagreement reflect a fundamental debate about tax policy, it does not undermine the basic fact that ta preferences are enormous. Indeed, most provisions that are preferences relative to an income-tax-based system are also preferences relative to a system built around a consumption tax. My colleague Eric Toder and I have estimated, for example, that about two-thirds of the dollar value of tax preferences identified by Treasury for 2007 would also be foregone revenue under a consumption tax.