There has been a steady growth of a narrative of: The teachers are solely responsible for low performance. Just about a year ago, Newsweek magazine had a cover story, called “The Key to Saving American Education.” And all over that cover was the phrase, we must fire bad teachers. And then, last fall came out this horrible movie we -called “Waiting for Superman,” that also blamed teachers for everything and said that poverty doesn’t matter and resources don’t matter, and that what we must do is to open lots of privately managed schools that don’t have unions. And this has been a steady drumbeat over the past year or two Go to the original…