I thought they - and the federal workers union - did not contribute to social security because of thier lucrative pension plan. Yeah, if they join the dreaded private sector they can contribute to SS.
Senators, reps, federal employees et al have been part of the Social Security system for about 25 years.
In-Depth Research - Legislative History
Senators and reps are also in the same pension plan as other federal employees (those feds hired since 1984): FERS (Federal Employees Retirement System).
Federal Employees Retirement System (FERS) Publications
Google Answers: Social Security for Senators and Reps
As of 2000, 409 retired members were receiving benefits under CSRS at
an average rate of $52,464 per year and 53 had retired under FERS with
$46,932 per year in average benefits. Members do not automatically
received lifetime pensions. How much they receive and how long they
receive it depends on many factors, including age, length of service
(including military) and choice of plans, etc. So, while it's
conceivable that some may receive pay-outs totalling more than a
million dollars by the time they die, it would be the exception, not
the rule...."