In the 1905 case of Jacobson v. Massachusetts, the U.S. Supreme Court upheld a Massachusetts law mandating vaccination against smallpox during an outbreak of the disease. The plaintiff, Henning Jacobson, refused to be vaccinated on grounds that it violated his personal liberty and could potentially harm his health. He was subsequently fined by local authorities for non-compliance with public health regulations. In its ruling, the court held that individual liberties may sometimes be curtailed when necessary to protect public health or safety under police power - a state's inherent authority to regulate activities within its borders in order to promote general welfare and security of its citizens. This landmark decision established precedence for government intervention in matters concerning public health emergencies.

In the dissenting opinion for Jacobson v. Massachusetts, Justice Harlan argued that while states have a right to enact laws for public health and safety, this power is not absolute and must be exercised in a reasonable manner that does not infringe upon personal liberties protected by the Constitution. He contended that compulsory vaccination could potentially lead to an abuse of state power if it were allowed without limitations or safeguards against potential harm to individuals. Furthermore, he believed there should be exceptions made for those who object on grounds of personal beliefs or medical conditions. In essence, his dissent emphasized the importance of individual rights and cautioned against unchecked governmental authority under the guise of public health measures.