The burden of the payroll tax is already enormous. Though the 12.4 percent rate is technically divided in half between employer and employee, workers end up paying the employer’s side of the tax through lower compensation. …Last year, the Social Security payroll tax raised $1.28 trillion. That’s almost three times what the corporate tax raised. Only the individual income tax raises more federal revenue. …it’s easy to see why the program is broke. The payroll tax rate has been the same since 1990, and revenue as a share of the economy has been roughly flat. The program used to run annual cash-flow surpluses but since 2010 has run deficits — because benefits are rising too quickly.