In the case of Real Silk Hosiery Mills v. City of Portland et al., 1924, the U.S Supreme Court ruled in favor of the city's right to regulate door-to-door salespeople. The plaintiff, Real Silk Hosiery Mills, a company that sold its products through door-to-door solicitation, challenged an ordinance by the City of Portland requiring permits for such activities. They argued it violated their rights under both state and federal constitutions. However, the court upheld this regulation as a valid exercise of police power aimed at preventing fraud and protecting residents' privacy against intrusive commercial practices. This decision affirmed local governments' authority to enact reasonable regulations on business operations within their jurisdictions for public welfare purposes.

In the dissenting opinion for REAL SILK HOSIERY MILLS v. CITY OF PORTLAND et al., Justice McReynolds disagreed with the majority's decision to uphold Portland’s licensing fee on out-of-state businesses, arguing that it violated the Commerce Clause of the U.S. Constitution by placing an undue burden on interstate commerce. He contended that this case was not about a city's right to regulate local affairs but rather its attempt to impose restrictions and fees on companies conducting business across state lines, which he believed was unconstitutional. Furthermore, he argued that if every municipality were allowed to charge such fees, it would create a significant barrier for businesses seeking to operate nationally or regionally and could potentially lead to economic protectionism at a local level.