Since Bernanke took over in 2006, the Consumer Price Index has risen at an average annual rate of 2.3 percent -- which, according to economist Mark Perry of the conservative American Enterprise Institute, gives him the best anti-inflation record of any Fed chairman in the past 40 years. In May, prices were up just 1.8 percent from a year before.
The problem with the U.S. economy in recent years has not been inflation but persistent weakness and unemployment. Nominal GDP, Sumner notes, has grown at the worst pace since Herbert Hoover was president.
Not everyone saw what was coming. This week, a news story in the Wall Street Journal compared hundreds of predictions made since 2009 by Fed officials. "The most accurate forecasts overall came from Yellen," the Journal found. "The least accurate forecasts came from central bank 'hawks,' those who feared Fed policies would trigger rising inflation."
One of the former hawks admits being wrong. Narayana Kocherlakota, head of the Federal Reserve Bank of Minneapolis, said last year, "Inflation is not coming in as hot as I expected. You have to learn from the data."
As every investor knows, past performance is no guarantee of future results. Just because Yellen had the foresight to push monetary expansion doesn't mean she's the person to rein it in when conditions change. But her ability to grasp realities that baffled other experts suggests she has a deeper comprehension of how the modern economy works.
What became clear last fall, as Republicans mocked polls that showed Mitt Romney trailing, is that the important divide in modern debates is not between the right and the left. It's between the people who follow dogma and the people who follow evidence. Yellen is one of the latter, but I'm willing to forgive her.