Seven years ago, the Federal Reserve and the Treasury Department bailed out the largest financial institutions in this country because they were considered too big to fail. But almost every one is bigger today than it was before the bailout. If any were to fail again, taxpayers could be on the hook for another bailout. To rein in Wall Street, we should begin by reforming the Federal Reserve, which oversees financial institutions. Unfortunately, an institution that was created to serve all Americans has been hijacked by the very bankers it regulates. What went wrong at the Fed? The chief executives of some of the largest banks in America are allowed to serve on its boards. During the Wall Street crisis of 2007, Jamie Dimon, the chief executive and chairman of JPMorgan Chase, served on the New York Fed's board of directors while his bank received more than $390 billion in financial assistance from the Fed. Next year, four of the 12 presidents at the regional Federal Reserve Banks will be former executives from one firm: Goldman Sachs. We would not tolerate the head of Exxon Mobil running the Environmental Protection Agency. And we should not allow big bank executives to serve on the boards of the main agency in charge of regulating financial institutions. Financial reforms must not stop with the central bank. We must reinstate Glass-Steagall and break up the too-big-to-fail financial institutions. The sad reality is that the Federal Reserve doesn't regulate Wall Street; Wall Street regulates the Fed.