Did the 30year fixed mortgage create the credit crisis?

Planet Money had an interesting podcast last Friday about Fannie Mae, Freddie Mac, and how the creation of the 30 year fixed mortgage led to the subprime mortgage crisis.  In the piece Bethany McLean & Joe Nocera are interviewed about their book entitled “All the Devils are Here“.  In a nutshell, the creation of Fannie Mae and the implicit guarantee of the Federal government ultimately led to the creation of a 30yr fixed mortgage, which morphed into more exotic loan options in the recent decade.  We all know how that story ends.  Anyways, it’s worth a listen if you have a few minutes.