Before the stock market and the broader economy can return to something that looks like normal, banks must start to lend the billions they are getting from the U.S. Treasury’s Troubled Asset Recovery Program, says Wharton finance professor Jeremy Siegel in an interview with Knowledge at Wharton. Banks should not be trying to improve their balance sheets by calling in loans to companies that have always paid on time, he adds. Siegel also discusses the government’s rescue of Citigroup and the proposed bailout of the U.S. auto industry. An edited transcript of the conversation follows. Knowledge at Wharton:  Professor Siegel, thank you so much for joining us today. We would like to talk first about the stock market, of course, beginning with its wild gyrations over the past few days, all driven by one news event or another. Are news headlines going to drive the market every day for the foreseeable future? Siegel:  Let’s put this in context.…