You might also be able to argue that debts that cannot be discharged in bankruptcy represent a form of indentured servitude. And that is illegal now in the US,

You might also be able to argue that debts that cannot be discharged in bankruptcy represent a form of indentured servitude. And that is illegal now in the US, thanks to the 13th Amendment. In fact, indentures were a better deal, because the indenturee was guaranteed to have the job necessary to fulfill the contract. Student loan issuers don't have to accept work in lieu of cash.