In the case of Charles A. Ramsay Company v. Associated Bill Posters of the United States and Canada et al., 1922, the Supreme Court ruled on a dispute involving antitrust laws and restraint of trade in relation to bill posting services across multiple states. The plaintiff, Charles A. Ramsay Company, alleged that Associated Bill Posters had created an illegal monopoly by controlling all outdoor advertising spaces in several cities throughout North America which violated Sherman Antitrust Act provisions against monopolies and restraints on interstate commerce. The defendants argued they were not engaged in interstate commerce as their business was confined within individual states' boundaries where they owned or leased billboard space for advertisements. However, the Supreme Court disagreed with this argument stating that while each transaction may occur within one state's borders, collectively these transactions constituted a significant part of interstate commerce due to their cumulative effect on pricing and availability across state lines. Therefore, it held that such activities could be regulated under federal law even though individually conducted within single states because together they formed part of an overall scheme affecting national trade.

In the dissenting opinion for Charles A. Ramsay Company v. Associated Bill Posters of the United States and Canada et al., Justice Holmes argued that there was no violation of antitrust laws in this case, as he believed that a monopoly is not illegal per se under these laws unless it restrains trade or commerce among several states or with foreign nations. He contended that monopolies can be legal if they are used to promote competition rather than suppress it, which he felt was true in this instance. Furthermore, Holmes asserted that the majority's decision failed to consider whether any actual harm had been done by the alleged monopoly; instead, they focused solely on its potential for abuse - an approach he disagreed with.