The Republicans have responded to the Democrats' calls for tax increases on the rich with calls for tax increases on "undertaxed" lower income Americans. The GOP does not consider the highly regressive payroll tax a tax, instead the GOP views payroll taxes as the equivalent of contributions to a savings account. Notice that the social security reformers do not call for lowering the payroll tax, instead they simply call for forcing workers to invest some of their money in the stock market instead of sending it all to the government. In fact, some of the biggest proponents of "privatizing" social security are hostile to cuts in the payroll tax rate.
Republicans also do not consider how their deficits increase the hidden tax of inflation. As the only member of Congress who understands Austrian economics could tell them, the inflation tax hits the middle and working classes the hardest.
As Alina points out the GOP is lucky that their opponents are the hapless Democrats, who are either unwilling or unable to make an issue out of the GOP's support for tax hikes on the poor.
