American politics and financial disaster

I do not understand how it is possible to extend the payroll tax cut and also extend the unemployment benefit at the same time. I understand that the payroll tax is used to fund the unemployment benefit and social security. If the payroll tax is cut, then the social security (i.e. old age pensions and unemployment benefit) has to be reduced - not extended. American politics has reach a ridiculous level. http://www.cnbc.com//id/45549974