Final answer:
A single seller's refusal to deal does not inherently violate Section 2 of the Sherman Act, but it could if it has anti-competitive effects or maintains monopoly power. Antitrust law balances these actions against market efficiency and consumer prices to assess the impact on competition and monopolies.
Step-by-step explanation:
The question revolves around the interpretation of Section 2 of the Sherman Act regarding a seller's unilateral refusal to deal. Under U.S. antitrust law, particularly the Sherman Anti-Trust Act, monopolistic practices are illegal. However, the act of a single seller choosing with whom they wish to do business does not necessarily violate the act. To be in violation, the refusal must contribute to monopolization or an attempt to monopolize. This means that the refusal must have an anticompetitive effect or must maintain the seller's monopoly power. While buyers and sellers act independently and compete, they also must be well informed and free to enter or leave the market. This ensures a competitive marketplace without unfair business practices. However, a seller with substantial market power may fall under scrutiny if their refusal to deal appears to suppress competition.
Contemporary understandings of antitrust law also balance the monopolist's actions against the market's efficiency and consumer prices. While companies have historically defended consolidation and market control by pointing at efficiency and lower prices, this defense must be weighed against the potential for anticompetitive behavior. Therefore, it's not simply the refusal to deal that's at issue; it's the impact that refusal has on the market and on maintaining a monopoly.