WITH April 15, comes the perennial debate over the fairness of the tax burden. Liberals say the rich pay too little; conservatives argue that the rich get soaked. Conservatives often cite these statistics: the top 5 percent of taxpayers pay 57 percent of federal income taxes, the top 1 percent 36 percent, and the bottom 80 percent a trifling 17 percent. But this argument ignores the payroll tax, which finances Social Security, as well as excise taxes on things like liquor or tobacco. These take their biggest bite, proportionally, from lower-income Americans. Income tax will account this year for 42...
