According to one theory of government involvement in the economy, regulation is the result of pressures from business, consumers, and environmental groups and results in regulation, which supports business and protects consumers, workers, and the environment. This theory or of regulation is examined in the first section of the chapter. According to more traditional theory, however, regulation is undertaken to ensure that the economic system operates in a manner consistent with the public interest and to overcome market failures. This is discussed in Sections 12-2 and 12-3 of this chapter. Section 12-4 summarizes U.S. antitrust laws, which are designed to enhance competition and forbid anticompetitive actions on the part of business firms. Section 12-5 examines the enforcement of antitrust laws and the recent deregulation movement. Section 12-6 deals with the regulation of international competition. Finally, Section 12-7 examines the effect of taxation on business decisions.