In the case of United States v. Boston & Maine Railroad et al., 1964, the U.S. Supreme Court ruled on a dispute involving railroad companies and their obligations under federal law to maintain certain passenger services. The Interstate Commerce Commission (ICC) had ordered several railroads, including Boston & Maine, to continue providing unprofitable passenger services that they wished to discontinue due to financial losses. The railroads argued that this order was an unconstitutional taking without just compensation in violation of the Fifth Amendment because it forced them into continued operation at a loss. The Supreme Court disagreed with the railroads' argument and upheld ICC's order for continuation of service by these carriers despite their financial difficulties. It held that while there might be circumstances where regulatory orders could constitute a 'taking', this was not one such instance as no physical property was taken from them; instead, they were required only to use their property in a particular manner which did not amount to confiscation or seizure. This ruling reaffirmed government’s power over private corporations when public interest is involved and clarified what constitutes ‘taking’ under Fifth Amendment.

In the dissenting opinion for United States v. Boston & Maine Railroad et al., 1964, it was argued that the Interstate Commerce Commission (ICC) should not have been allowed to approve a merger between two railroad companies without considering its impact on other railroads and public interest. The dissenting justices believed that this decision would lead to an unhealthy concentration of power in the hands of a few large corporations, which could potentially harm competition and consumer interests. They also criticized the majority's interpretation of Section 5(2)(b) of the Interstate Commerce Act, arguing that it did not give ICC such broad authority to approve mergers without thorough investigation into their potential effects on industry competition and public welfare. Furthermore, they expressed concern about setting a precedent where regulatory agencies could make significant decisions affecting entire industries with minimal judicial review or oversight.