How high is the marginal tax rate on each additional dollar the average American earns? In other words, if you got a raise of one dollar, how much of that dollar would be taxed away? These rates are already high, and they’re getting higher next year. A middle-class taxpayer’s income is subject to a 25 percent federal income tax. Then there is the federal Social Security and Medicare payroll tax of 13.3 percent in 2012—5.65 percent of that is removed from the employee’s paycheck, and the remaining 7.65 percent is paid by the employer. (In reality, the employee pays the...