When New Jersey governor Jon Corzine lost his reelection bid to Chris Christie in 2009, part of his defeat in a Democratic state was blamed on the post-Lehman mood. Having experience as a top executive at Goldman Sachs just didn’t help. But in March 2010, Corzine returned to Wall Street where he hoped to bolster his reputation, helming broker-dealer powerhouse MF Global. On Monday, the company announced it had filed for Chapter 11 bankruptcy protection.