CDOs weren't illegal. Securitization still isn't illegal.
As bad as the mortgage bubble was, the same mechanism is behind the
securitization of student loans, with roughly the same toxic brew of Ratings-Agency shenanigans backed by a state fiduciary (Sallie Mae) combining to snowball a massive bubble. That article is by Mohamed el-Erian who used to run PIMCO, one of the world's largest private equity joints.
He's too nice to point out a major similarity with subprimes and for-profit colleges incentivized to milk public-aid backed student loans: just like handing out a 500k mortgage loan to a part-time stripper is probably unwise, handing out a 300k student loan to a feminist dance theory graduate is just as likely to produce a return.