In 1937 Roosevelt was using surplus payroll taxes to fund general expenditures.
If interested this is a great book on the history of entitlements in the U.S. It's not a partisan book. It starts at the revolutionary war and goes up to today. It's a great history.
https://www.amazon.com/High-Cost-Good-Intentions-Entitlement/dp/1503603547
If there was a surplus in payroll taxes that surplus is used to buy treasuries as required by the original SS law. The money used to purchase those treasuries is then used by government in the (usually) general fund. It is no different than other purchases of treasuries which the government borrows and repays with interest.
It makes more sense than just letting those surplus SS taxes sit in the trust fund earning no interest while government goes sells treasuries on the open market which puts pressure on interest rates and borrowing. Either way, the government is borrowing money which must be repaid with interest. It is better to borrow your own money and repay yourself with interest than borrowing from the public and paying them interest.
My point is that the government did not raid SS and only followed the law which was a logical thing to do. SS is not having revenue problems because Congress took the money because that $2.8 trillion surplus is in the SS trust fund and currently being used for SS benefits. Congress has to come up with the money to repay those treasuries but it would have to do that even with money it borrowed from the public.
Too often we hear SS would be in good shape IF Congress had not "stolen" the money to spend on war (liberals) or welfare (conservatives).
Thanks for the information-looks like a useful book.