The banksters have a damn good track record when it comes to skating on their crimes. My money’s on them.
Since they could no doubt replace the Obama Administration with an equally compliant Gingrich or Romney Administration by crooking a little finger, I don't expect any serious attempt to investigate MF Global. Some mid-level executive will be hung out to dry, and told if he "testifies right" he might live long enough to see his family again in fifteen years.
The bigger problem for the Powers That Be is that MF Global was just a crack in the dike, and there are many more coming. We haven't seen what lengths they will go to to hold on to power, but I expect they will end up making Chairman Mao look virtuous.