Govt employees on CRCS do not pay social security taxes. BTW, that includes all members of Congress
No federal employee hired after 1984 is covered by CSRS, including congress. They are covered by FERS and pay full SS and medicare, as well as federal, state, and local taxes. They also contribute to a 401K (with matching funds), similar to most private industry. Only those that were hired prior to 1984 and are still around are CSRS. CSRS employees do not pay SS (and are not eligible to collect), they contribute 7% of pay to the retirement fund, and pay full medicare tax (1.3%?). No doubt, CSRS is/was a great plan but long gone for anyone hired in the last 30 years. But it is probably not as good as some union plans were or that some teacher plans are now (which are also taxpayer funded for the most part).