The U.S. Supreme Court case Travelers Health Association et al. v. Virginia ex rel. State Corporation Commission in 1949 revolved around the issue of whether a state could regulate an out-of-state corporation's mail order insurance business within its borders without violating the Commerce Clause of the Constitution, which gives Congress power to regulate interstate commerce. Travelers Health Association, a Nebraska-based company, sold accident and health insurance policies through direct mail across states including Virginia but was not licensed there as required by state law for insurers operating within its boundaries. Virginia sought to prevent Travelers from conducting business in their state unless it complied with local licensing regulations; however, Travelers argued that this violated their rights under the Commerce Clause because they were engaged in interstate commerce. The Supreme Court ruled against Travelers stating that while selling insurance does involve aspects of commerce crossing state lines (mailing contracts), it also involves substantial activities confined within one particular place (the insured person’s home). Therefore, these transactions are subject to regulation by individual states where those homes are located.

In the dissenting opinion for Travelers Health Association v. Virginia, Justice Jackson argued that the majority's decision to uphold a state law prohibiting out-of-state mail order insurance companies from operating without a license in Virginia was an overreach of state power and violated the Commerce Clause of the Constitution. He contended that this ruling would allow states to regulate interstate commerce beyond their borders, which is contrary to constitutional principles. Furthermore, he expressed concern about potential negative impacts on national economic unity and efficiency if each state could impose its own regulations on businesses operating across state lines via mail or other means. In his view, such matters should be regulated by federal law rather than individual states' laws.