Commentary When a writer starts a new column, his first battle is to justify why people should read it. Paul Krugman has just made that task much easier for me, by publishing a column on money that, to use his favorite phrase, is “all wrong.” The crucial point at which Krugman gets it “all wrong” —yes, a Nobel Prize winner in Economics is wrong about money—is his assumption that, when they lend, banks lend out reserves: Since the 2008 financial crisis, however, banks have been voluntarily holding vast excess reserves, apparently because they don’t see enough good lending opportunities. If you’ve studied economics, you might think there’s nothing wrong with that statement, because that’s what the textbooks tell you: banks take in deposits from some customers, and then lend out the reserves these deposits create to other customers. But in 2014, the Bank of England said that the textbooks were …