You can squeeze a few thousand retired civil servants, but you can't squeeze all of America. The only solution to an impending Social Security crisis is "monetary easing".
which, of course will screw the rich by draining the stock markets and making institutional lenders poorer.
Is Social Security mandatory? I've been wondering about this.
If you mean, "can you opt out of paying for it and then not collect benefits when you retire", the answer is no. Your employer is required to withhold it from your salary (or if you're self-employed, you are required to pay the tax yourself).
And a lot of the time, if you’re a Green Card holder, or emigrant citizen, not only are they required to withhold it, but you’re also forbidden from claiming it.