Is there really even such a trust fund? I thought that SS money goes into the general fund, to be spent as fast as it's collected.
Yep, there is a SS trust fund...most of it invested in “Special Issue” US Treasury T-Bills/bonds. By buying US bonds I guess you could say the SS Trust Fund allows Congress to spend more $$.
https://www.investopedia.com/ask/answers/110614/how-social-security-trust-fund-invested.asp