Timothy Geithner, Secretary of the Treasury
As head of the New York branch of the Federal Reserve in 2008, Geithner oversaw the juiciest parts of the AIG bailout-slash-boondoggle. He's one of the most subtle Un-Jailed Americans working today.
After taxpayers gave AIG $170-plus billion, it overpaid banks like Goldman Sachs and Deutsche Bank $62 billion for derivative products which were, not coincidentally, insured by AIG. These derivates were worth so little that the payment saved-slash-earned those banks at least $13 billion. It was, essentially, a backdoor bailout.
Seems like a standard stupid-slash-self-serving move, until you realize that Timmy's New York Fed forced-slash-pressured AIG to keep details of the transaction hidden from the public… The public that paid for them. The NY Fed thought disclosing AIG's bad business might harm AIG's ability to do business - bad business - much like disclosing an affair harms a man's ability to get some on the side.
The NY Fed's veil of secrecy kept AIG's questionable move hidden long enough to take root. So, while Geithner didn't personally steal public money, he enabled powerful financial forces to do so with neither disclosure nor repercussion. For that, he remains, not in jail.