@michael_martinez oh, it's the opposite: the law REQUIRES the money to be used for other purposes.
By law Social Security revenues must be deposited into the Treasury just like all other tax collections, where it gets spent just like all other revenues.
Go a step deeper. What is the Trust Fund?
By law, the Managing Trustee must invest money collected into the Trust Fund into obligations of the US, which is to say, transfer it to the US Treasury.
To say that Trust Funds may not be used for budgeting doesn't change the use of the cash received by the Treasury after the Trust Fund purchases those obligations.