It has long been obvious to all observers -- to economists, to politicians, to anti-deficit groups, to the ratings agencies -- that closing fiscal gaps will require tax increases, or the closure of big tax loopholes, or significant tax reform that will raise significantly larger sums of tax revenue than the system does now. Today, taxes as a percentage of GDP are at historic lows. Marginal rates on income and investments are at historic lows. Corporate tax receipts as a percentage of GDP are at historic lows. Perhaps taxes don't need to rise this year or next, but they do...