In the case of William A. Ensign v. Commonwealth of Pennsylvania, 1912, the U.S Supreme Court dealt with a dispute over inheritance tax laws in Pennsylvania. The appellant, William A. Ensign was an executor to his father's estate and challenged the state's right to impose taxes on certain portions of it that were held outside its jurisdiction at the time of death - specifically stocks in corporations located out-of-state but owned by a resident within Pennsylvania at their time of death. Ensign argued this taxation violated both due process and equal protection clauses under Fourteenth Amendment as well as interfering with interstate commerce contrary to Article I Section 8 Clause 3 (Commerce Clause) of US Constitution. However, after deliberation, court upheld validity of such taxes stating they were not unconstitutional or discriminatory since they applied uniformly across all residents regardless where property is physically located; also ruling there was no interference with interstate commerce because these are essentially non-business personal assets subject only to probate proceedings upon owner’s demise rather than being actively traded goods/services crossing state lines for commercial purposes.

In the dissenting opinion for William A. Ensign v. Commonwealth of Pennsylvania, Justice Oliver Wendell Holmes Jr., disagreed with the majority's decision to uphold a Pennsylvania law that taxed corporations based on their capital stock value and indebtedness. He argued that this tax was unconstitutional because it violated the Fourteenth Amendment's Equal Protection Clause by unfairly discriminating against out-of-state businesses operating in Pennsylvania. According to Holmes, since local companies were only taxed on their property within the state while foreign corporations were taxed on all their assets regardless of location, there was an unjustifiable disparity between how these two groups were treated under this taxation scheme. Furthermore, he contended that such discrimination could not be justified by claiming it as compensation for granting foreign corporations permission to do business in Pennsylvania because they already paid fees for obtaining charters or licenses from the state government.