In 1864 during the Civil War, U. S. Army officers in Indiana where there was no fighting occurring arrested Lambdin P. Milligan and some other anti-war Democrats. They were charged with conspiracy to seize munitions at a federal arsenal and to free Confederate prisoners being held in northern prisons. The defendants could have been tried in civilian courts in Indiana which were open and operating, but military officials chose to have them tried instead by military commissions. These military commissions found Milligan and two other defendants guilty and sentenced them to be hanged. On appeal to the Supreme Court, all nine justices agreed that the military courts had no jurisdiction to hear the cases and that Milligan and the other defendants had to be released. In his opinion for the Court, Justice David Davis noted that the Constitution was not suspended in time of emergency and wrote that it was “a law for rulers and people, equally in time of war and peace.” He pointed out that military trial of civilians was not permitted where civilian courts were open and operating and that neither the president nor Congress could otherwise authorize such trials. The Court’s ruling also defined conditions necessary for martial law to be declared and asserted civilian power over the military. “Martial law cannot arise from a threatened invasion. The necessity must be actual and present; the invasion real, such as effectually closes the courts and deposes the civil administration….As necessity creates the rule, so it limits its duration; for, if this government is continued after the courts are reinstated, it is a gross usurpation of power. Martial rule can never exist where the courts are open, and in the proper and unobstructed exercise of their jurisdiction. It is also confined to the locality of actual war.”

Based on its power to protect the public health, safety, and welfare, the Louisiana legislature passed a law that put about a thousand local slaughterhouses out of business by granting a monopoly in New Orleans to the Crescent City Landing and Slaughterhouse Company. The butchers who were put out of business were white, and they argued that their right to pursue a lawful profession was protected from state interference by either the Privileges and Immunities Clause or the Due Process of Law Clause of the Fourteenth Amendment. This was the Supreme Court’s first opportunity to interpret the meaning of the Fourteenth Amendment which had only recently been added to the Constitution in 1868.

When the Slaughterhouse Cases reached the Supreme Court on appeal in 1873, a majority of the Court began its decision by declaring that the meaning of the recently added Fourteenth Amendment needed to be considered in light of its original purpose: namely ensuring the freedom of former slaves. The majority then proceeded to define the scope of the Privileges and Immunities Clause very narrowly by arguing that the clause referred only to “very few express limitations which the Federal Constitution imposed upon the States-such, for instance, as the prohibition against ex post facto laws, bills of attainder, and laws impairing the obligation of contracts,” along with seeking the government’s protection while “on the high seas” as well as a general right to interact with government. However, the majority continued, the clause did not “bring within the power of Congress the entire domain of civil rights heretofore belonging exclusively to the States.” This severe limitation of the meaning of the privileges and immunities clause remains controversial and has never been overruled. As a result, the clause is hardly ever invoked in litigation today.

Next, the majority of the Court dismissed the due process of law claim. Even assuming a liberty interest in the right to pursue a lawful profession, the Court’s majority held that the legislature’s monopoly law was a legitimate regulation as a public health measure. Using its so-called “police power,” a state could legitimately decide that the concentration of the slaughterhouse business in one area would reduce the spread of disease associated with the slaughtering of animals.

In 1875, the Illinois legislature, dominated by members sympathetic to the Grange (a group supporting agriculture), passed a law creating a commission to set the rates that privately owned grain elevators could charge farmers for grain storage. The law only applied to one city: Chicago. In the city of Chicago nine owners controlled 31 grain elevators thereby having a virtual monopoly over the rates they could charge farmers to store their wheat. Munn, one of these owners, sued on the grounds that the Illinois law denied him his property rights in violation of the due process of law clause of the Fourteenth Amendment.

A majority of the Supreme Court upheld the Illinois law and ruled that it was clearly within the police power of the state to protect public health, safety, and welfare. The majority reasoned that once private property is “affected with a public interest” the state may use its police power to regulate it in the public interest. For example, taxi companies are privately owned but their rates can be regulated by the state in the public interest. The case was considered progressive for its time because the usually conservative Supreme Court was noted for protecting property rights. Munn had argued that the power to set rates, if it existed at all, belonged to Congress under its constitutionally granted power to regulate interstate commerce. While conceding that interstate commerce was affected, the Court’s majority held that, in the absence of Congressional action, Illinois was free to do so under its police power.

Section 5 of the Fourteenth Amendment added to the Constitution in 1868 authorized the U. S. Congress to enforce the amendment by appropriate legislation. Using this enforcement clause as its constitutional authority, Congress passed the Civil Rights Act of 1875 which made it unlawful to discriminate on the basis of race in hotels, theatres, places of amusement, and other places of public accommodation. African Americans in five cases from lower courts in California, Kansas, Missouri, New Jersey, and Tennessee sued theaters, hotels, and railroads that refused to serve them. The issue in the five cases, which the Supreme Court consolidated and decided together as The Civil Rights Cases, was the constitutionality of the Civil Rights Act of 1875.

By a vote of 8-1, with only Justice John Marshall Harlan I dissenting, the Supreme Court declared the Civil Rights Act of 1875 unconstitutional on the grounds that the Amendment was added only to outlaw public, not private, discrimination. The Court’s majority introduced the concept of “state action” for purposes of showing discrimination. The majority pointed out that the amendment provides that “no state” shall deny a person the equal protection of the law. The majority interpreted this to mean that states may not adopt laws that discriminate on the basis of race, but the refusal of a hotel owner to serve African Americans is private discrimination, and the Amendment has nothing to do with that. In a powerful dissent, Justice Harlan wrote that in his view “the substance and spirit of the recent amendments to the Constitution have been sacrificed by a subtle and ingenious verbal criticism.”

In 1964, the U. S. Congress adopted the Civil Rights Act of 1964 which, like the 1875 Civil Rights Act, outlawed racial discrimination in public accommodations. However, recalling the reasoning of the Supreme Court’s majority in the 1883 Civil Rights Cases, this time Congress based its constitutional authority for passing the law not on the Fourteenth Amendment but on the commerce clause of Article I, Section 8 of the Constitution. When the Civil Rights Act of 1964 was challenged as to its constitutionality, unlike the Civil Rights Act of 1875, the Supreme Court unanimously upheld its constitutionality.