Dr. Paul Craig Roberts was the guest in this Tuesday, Dec. 11th, 2012 edition of One-on-One with Greg Hunter of USAWatchdog.com. Dr. Roberts thinks there is “an impending collapse of the exchange value,” and the U.S. dollar could unexpectedly plunge in buying power. Dr. Roberts contends, “All of a sudden, people will walk into Walmart, as usual, and they’ll think…