FOREIGN COMPETITION AND THE MARKET POWER INQUIRY

It is obvious that foreign suppliers sometimes have a substantial effect on the markets in which U.S. consumers buy. But how much influence does any set of foreign competitors have in any particular domestic market which is under scrutiny by a government agency or antitrust court in the United States? Stated another way, how can we assess with any degree of confidence the presence, intensity, and future continuity of foreign competitors in the market?