The Justice Department and the Securities and Exchange Commission have broad powers to root out and punish financial fraud. The Interagency Financial Fraud Task Force, formed last November, is an Obama-era innovation that enhances the government's ability to track down financial criminals. As we look back on the last two years' revelations about Wall Street misbehavior, then, it seems reasonable to ask the question: What's a banker gotta do to get arrested in this town? We're not talking about the "show up with your attorney and we'll work out a settlement" kind of arrest, either.