In the 1909 case of International Textbook Company v. Pigg, the U.S. Supreme Court ruled in favor of International Textbook Company, overturning a decision by the state of Indiana that had imposed restrictions on interstate commerce. The company was an educational institution offering correspondence courses to students across states and internationally. It used agents who would solicit prospective students and enter into contracts with them for these courses, which were then sent through mail from Pennsylvania where it was based. The State of Indiana required such companies to obtain a license before operating within its borders under its Private Employment Agency Act but the company argued this violated their rights under Article I Section 8 Clause 3 (the Commerce Clause) of the Constitution as they were engaged in interstate commerce. The court agreed with International Textbook Company stating that while states have power over local matters affecting public policy or health, they cannot interfere with interstate commerce unless expressly authorized by Congress - which wasn't applicable here.

In the dissenting opinion for International Textbook Company v. Pigg, Justice Harlan argued that the majority's decision was inconsistent with previous rulings of the Court and violated principles of federalism. He contended that states have a right to regulate their own internal commerce as long as it does not interfere with interstate commerce or violate any other constitutional provision. In this case, he believed that Kansas had acted within its rights in requiring corporations doing business within its borders to obtain a license and pay an annual fee. The fact that some aspects of these corporations' operations involved interstate commerce did not exempt them from state regulation entirely; rather, they should be subject to both state and federal laws where appropriate. Furthermore, he disagreed with the majority's interpretation of what constitutes "doing business" in a particular state - arguing instead for a broader definition which would include more than just maintaining an office or having agents present there.