The commerce clause is a power granted to the US Congress in Article I, Section 8 of the United States Constitution; it gives Congress the power “to regulate commerce with foreign nations, and among the several states, and with the Indian tribes.” The different meanings of commerce—trade and interaction—have left the clause open to interpretation. A series of United States Supreme Court cases have shaped the understanding of the commerce clause, broadening its applications to such issues as navigation, migration and discrimination.
The first case to expand the power of Congress under the commerce clause was Gibbons v. Ogden in 1824. The Supreme Court ruled that a monopoly on steamboat navigation granted by the state of New York was invalid because it inhibited interstate commerce between New Jersey and New York. This ruling was significant because it established the applicability of the commerce clause beyond issues of interstate trade to include interstate navigation.
The Supreme Court also used the commerce clause to support free interstate migration in 1941. California attempted to limit the number of migrants who were coming to the state from the dust bowl. The law made bringing non-resident indigents into California a crime. Edwards v. California challenged this law, and the court found that people were “articles of commerce,” and thus the flow of migrants was a matter for Congress, rather than the individual states, to regulate.
In the 1960s, the Supreme Court further extended the commerce clause by using it to justify legislation against discrimination by non-state actors—entities that don't represent or work in the interest of a government body. Previously, the equal protection rights guaranteed by the Fourteenth Amendment provided protection from racial discrimination only against state actors—those acting on behalf of the government—so private businesses were not legally bound to treat all races equally. In Heart of Atlanta Motel v. United States in 1964, the court found that Congress could regulate businesses whose customers came primarily from other states. In the same year, the court's decision in Katzenbach v. McClung applied the commerce clause to a restaurant after determining that though the restaurant primarily served locals, its food came from other states. These two decisions established the power of the Civil Rights Act of 1964 to include private businesses.
While the Supreme Court has allowed Congress a variety of powers under the commerce clause, it has also rejected some tenuous links to the clause. One example of this is Congress’s attempt in 1995 to ban guns from school zones on the grounds that the presence of firearms would create an environment that was not conducive to free commerce. The commerce clause has many applications, but it does serve as a check on Congress’s power in some instances.