According to Michael Porter's Five Forces model, the best industries for economic profit are characterized by low threat of entry, low buyer power, low supplier power, low threat from substitutes, and low levels of rivalry between existing firms. Prior to beginning work on this discussion, read the Trefis Team's article, Altria in the U.S. Tobacco Industry - A Porter's Five Forces Analysis(Links to an external site.). Evaluate the U.S. tobacco industry using Michael Porter's Five Forces model. Based on a Porter's Five Forces analysis, do you think the U.S. tobacco industry can continue to generate economic profit? Why or why not? What are other sources of economic profit for a firm? Discuss in detail.