Bernanke’s unconventional programs have been implemented in two phases. During the financial crisis of 2007–09, he bailed out a handful of large banks and devised a series of innovative lending operations to disperse credit to banks, small businesses, and consumers (virtually all of these loans have been repaid at a profit to taxpayers). He also lowered short-term interest rates to nearly zero and made private banks run a gantlet of stress tests to ensure some minimal level of solvency going forward. Although fierce anger against the bailouts persists, there is little argument that this first stage was a success. However untidily the rescue was managed, the financial crisis is over.

In the second stage, Bernanke has sought to revive a weak economy by maintaining short-term interest rates at close to zero, and by purchasing, in vast quantities, long-term Treasury bonds and mortgage-backed securities. This second phase has been, if anything, more controversial than the first. Its success is much harder to measure (we have no way of knowing whether the economy’s improvement would have been less robust, and how much so, without Bernanke’s efforts). And it has exposed Bernanke to charges of meddling too deeply in the private sector, of disrupting the economy’s natural rhythms long past the point when such intervention is necessary. In particular, critics note that the Fed has stuffed the banking system with $1.5 trillion in excess reserves—money for which the banks have no present use, loan demand being modest, but which could one day spark an epidemic of inflation.

Michael Bordo, a monetary historian at Rutgers, told me that in this second phase, “Bernanke has moved into areas that were quite different from what the framers had in mind. One of the risks the Fed is facing is of overreach.” Similar criticisms have been sounded, with notably less restraint, on the presidential campaign trail. Texas Governor Rick Perry said in August that Bernanke, who steered the economy out of its worst slump since the Great Depression, was “almost treacherous—or treasonous in my opinion.” He also declared, famously, “If this guy prints more money between now and the election, I dunno what y’all would do to him in Iowa, but we would treat him pretty ugly down in Texas.” Most of the other GOP candidates struggled to find a way to attack Bernanke without sounding like they were, just yet, rounding up a lynching party. Newt Gingrich called Bernanke “the most inflationary, dangerous” Fed chairman “in history”—a remarkable statement given that during Bernanke’s tenure, inflation as measured by the Consumer Price Index has averaged 2.4 percent, lower than that under any other Fed chief since the Vietnam War. Mitt Romney, who had previously praised Bernanke for doing a good job, promised in September that if elected he would replace him, as did Herman Cain (Bernanke’s term expires in 2014). Ron Paul, a proponent of returning to the gold standard, in November called the Fed, which has been off the gold standard since 1971, “immoral.” In January, partly on the strength of his enmity toward the Fed, Paul finished a close third in the Iowa caucuses and second in the New Hampshire primary. “If the Fed had to be rechartered now, God help us,” Alan Blinder, a Princeton scholar who was the Fed vice chairman in the 1990s, told me.