In its almost 100-year history, the Fed had never bought one mortgage bond. Now my program was buying so many each day through active, unscripted trading that we constantly risked driving bond prices too high and crashing global confidence in key financial markets. We were working feverishly to preserve the impression that the Fed knew what it was doing.

It wasn’t long before my old doubts resurfaced. Despite the Fed’s rhetoric, my program wasn’t helping to make credit any more accessible for the average American. The banks were only issuing fewer and fewer loans. More insidiously, whatever credit they were extending wasn’t getting much cheaper. QE may have been driving down the wholesale cost for banks to make loans, but Wall Street was pocketing most of the extra cash.

From the trenches, several other Fed managers also began voicing the concern that QE wasn’t working as planned. Our warnings fell on deaf ears. In the past, Fed leaders—even if they ultimately erred—would have worried obsessively about the costs versus the benefits of any major initiative. Now the only obsession seemed to be with the newest survey of financial-market expectations or the latest in-person feedback from Wall Street’s leading bankers and hedge-fund managers. Sorry, U.S. taxpayer.

Trading for the first round of QE ended on March 31, 2010. The final results confirmed that, while there had been only trivial relief for Main Street, the U.S. central bank’s bond purchases had been an absolute coup for Wall Street. The banks hadn’t just benefited from the lower cost of making loans. They’d also enjoyed huge capital gains on the rising values of their securities holdings and fat commissions from brokering most of the Fed’s QE transactions. Wall Street had experienced its most profitable year ever in 2009, and 2010 was starting off in much the same way.

You’d think the Fed would have finally stopped to question the wisdom of QE. Think again. Only a few months later—after a 14% drop in the U.S. stock market and renewed weakening in the banking sector—the Fed announced a new round of bond buying: QE2. Germany’s finance minister, Wolfgang Schäuble, immediately called the decision “clueless.”

That was when I realized the Fed had lost any remaining ability to think independently from Wall Street. Demoralized, I returned to the private sector.