Wal-Mart Stores Inc., the nation's largest merchandise importer, this year will launch a "Made-in-America"-buying campaign designed to increase purchases of goods from domestic suppliers, Bill Simon, the retailer's president and chief executive officer of U.S. operations, announced last week at the National Retail Federation's annual convention. Simon said Walmart and Sam's Club will buy an additional $50 billion in U.S. products during the next 10 years. The compan...