When the federal government borrows funds, it pays interest. That interest is paid back from future tax receipts.
To tell the government not to spend funds it borrows from social security. Is to tell it not to borrow from Social Security. And since loaning funds to the Federal government is the only investment Social Security is allowed to make, it's effectively telling Social Security to put the funds under a mattress and never invest them and never collect interest.
Yeah, I know. I wanted "mc6809e" to answer that question.
What I really wanted to say was: "Listen, you maroon (mc6809e), that interest is paid by future taxes." But I was trying to be polite.