What happened was, everyone made fun of Al Gore when he suggested that the government should not be allowed to borrow SS money for other purposes. They reduced his well-thought-out arguments to derisively repeating the word "lockbox" to the tune of "nyaa nyaa nyaa nyaa nyaa" as though that made him wrong. And then proceeded to borrow the hell out of SS to fund wars and tax cuts for the wealthy.
Now, when the US Govt borrows, it's not like your cousin Ernie. There's collateral, in the form of US Treasury Bonds. Not IOUs. These are interest bearing financial instruments, the kind we all used to buy for our kids to help build a college funds. And yet morons like Tom Coburn are spouting nonsense like this:
“We have stolen $2.6 trillion from it. We put paper money in there...[snip] ...There's no question that there's an IOU in there,” Coburn said. “But our country’s borrowing $4 billion a day. There’s no question, if we had the money, we could wait 10 or 15 or 20 years to fix Social Security.
It's like this: suppose you put a bunch of cash in your checking account. The bank uses that money to buy bonds. Then when you go to pay the mortgage, they say "sorry, we stole your money, all that's left is an IOU." Then they foreclose your house.
That's essentially what they're trying to get away with.