There are economists, like Steve Keen, who argued that subprime mortgage crisis and financial crisis in general was a Ponzi scheme. And I would say it's pretty

There are economists, like Steve Keen, who argued that subprime mortgage crisis and financial crisis in general was a Ponzi scheme. And I would say it's pretty obvious to most people that it essentially was. Madoff could say, in his defense, "I don't know this was a Ponzi scheme, I was just incompetent". At that's similar to what these bankers are saying. We don't accept it as a defense, though; we just prosecute it. The point is, there is no strict line between incompetence and fraud. Every fraud can claim incompetence. The unfortunate truth is that the U.S. indeed prosecutes _obviously_ bad business decisions. Just not in the cases where the fish is big enough. (The same is actually true in my country, Czech Republic.)