Aldi and Lidl, Germany’s toughest discount food retailers, are invading the US. Both operate small, efficient no frill self serve supermarkets with a strong non-food assortment, and very low prices. Both have permanently changed the competitive landscape wherever they have gone. Lidl is about to open its U.S. headquarter in Arlington, Virginia and a distribution center in Alamance County, North Carolina. These are early steps in its U.S. invasion by this formidable company that operates about 11,000 stores in 26 countries throughout Europe. I am told that the company has already selected 80 locations in the Greater Washington, D.C. area...