There has been no raid of SS funds. When SS revenue is received, it is put into non-market, interest bearing T-bills, which are deposited into the SSTF.
The way SS works is that today’s workers pay for today’s retirees. Baby boomers are retiring at 10,000 a day and will continue to do so until 2030. Retirees are living longer and there are fewer workers to support the system. In 1950 there were 16 workers for every retiree; today, there are less than three; and by 2030 there will just two workers for every retiree.
In order to make SS solvent, you need to either raise taxes or reduce benefits or do some combination of those. From an actuarial basis, SS is unsustainable as currently structured.
LBJ put S.S. into the unified budget, which Congress has borrowed $2.9 trillion from Social Security. So it’s just a matter of semantics. Or kind of like in the movie Dumb and Dumber were the guys got a briefcase full of handwritten IOUs! So yep the Congressional IOUs are still there, go luck getting Congress to repay.