At the height of the housing crisis, it was estimated that 11 million homes in America were mortgaged for more than they were worth. That debt crisis may soon be dwarfed—if it hasn’t been already—by the student loan debt problem:

With college enrollment growing, student debt has stretched to a record number of U.S. households — nearly 1 in 5 — with the biggest burdens falling on the young and poor.

The analysis by the Pew Research Center found that 22.4 million households, or 19 percent, had college debt in 2010. That is double the share in 1989, and up from 15 percent in 2007, just prior to the recession — representing the biggest three-year increase in student debt in more than two decades.

Unlike an negative equity mortgage, student load debt is not dischargeable in a bankruptcy. It’s also non-transferable—the college degree that was “bought” with the debt cannot be sold or traded. That makes degrees that are not “marketable” or that were acquired for reasons of personal growth an expensive luxury good.

Obviously many people (including me, with some qualifications) believe that the value of obtaining a liberal education is worth taking on debt. But what about graduates who will receive neither a life-broadening education nor a vocationally useful skill-set from getting a college degree? Should we continue to encourage them to take on debt to pay for higher education?