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Q5: Is it true that members of Congress do not have to pay into Social Security?
A: No, it is not true. All members of Congress, the President and Vice President, Federal judges, and most political appointees, were covered under the Social Security program starting in January 1984. They pay into the system just like everyone else. Thus all members of Congress, no matter how long they have been in office, have been paying into the Social Security system since January 1984.
(Prior to this time, most Federal government workers and officials were participants in the Civil Service Retirement System (CSRS) which came into being in 1920--15 years before the Social Security system was formed. For this reason, historically, Federal employees were not participants in the Social Security system.)
Employees of the three branches of the federal government, were also covered starting in January 1984, under the 1983 law--but with some special transition rules.
1) Executive and judicial branch employees hired before January 1, 1984 were given a one-time irrevocable choice of whether to switch to Social Security or stay under the old CSRS. (Rehired employees--other than rehired annuitants--are treated like new employees if their break-in-service was more than a year.)
2) Employees of the legislative branch who were not participating in the CSRS system were mandatorily covered, regardless of when their service began. Those who were in the CSRS system were given the same one-time choice as employees in the executive and judicial branches.
3) All federal employees hired on or after January 1, 1984 are mandatorily covered under Social Security--the CSRS system is not an option for them.
So there are still some Federal employees, those first hired prior to January 1984, who are not participants in the Social Security system. All other Federal government employees participate in Social Security like everyone else.
This change was part of the 1983 Amendments to Social Security. You can find a summary of the 1983 amendments elsewhere on this site.
SOURCE: http://www.ssa.gov/history/hfaq.html
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