United States v. American Bell Telephone Company was a Supreme Court case that was decided in 1892. The case involved the United States government suing the American Bell Telephone Company for violating the Sherman Antitrust Act. The government argued that the company had created a monopoly in the telephone industry by buying out its competitors and controlling the market. The Supreme Court ruled in favor of the government, finding that the company had violated the Sherman Antitrust Act and ordering it to be broken up into several smaller companies. This case established the precedent that companies could not use their market power to create monopolies and that the government had the power to intervene in such cases. The decision in this case was a major victory for the government and helped to shape the modern antitrust laws that are still in place today.

In the dissenting opinion of United States v. American Bell Telephone Company, Justice Harlan argued that the government's attempt to break up AT&T’s monopoly was unconstitutional and violated due process. He believed that Congress did not have authority under the Sherman Antitrust Act to interfere with private contracts between AT&T and its customers, as it had done in this case. Furthermore, he argued that by forcing AT&T to divest itself of certain assets without providing any compensation for them constituted a taking of property without just compensation in violation of the Fifth Amendment. In addition, Justice Harlan felt that since there were no allegations or evidence presented at trial showing any anti-competitive behavior on behalf of AT&T which would justify breaking up their monopoly power then such action should be considered an abuse of governmental power over private enterprise and thus unconstitutional according to established precedent set forth in previous Supreme Court cases.