Social Security
Unfortunately, there is no Social Security money "laying around," and never was. The money gets dumped into the kitty the second it hits Washington, and replaced with a skiploader full of I.O.U.s. No trust fund. Just Social Security checks paid for on the fly by current taxpayers. You know...like welfare.
Social Security isn't a bank account full of cash, it's a government promise to keep the checks coming, no matter what. And you know what? They will. No matter what happens to the budget, somehow they'll scrape up enough to keep those checks in the mail, because they know if they don't, it'll be them being scraped up.
