In the case of Duluth and Iron Range Railroad Company v. St. Louis County, 1900, the U.S Supreme Court was tasked with determining whether a Minnesota state law that imposed taxes on iron ore mined from leased lands violated the Contract Clause of the Constitution. The railroad company argued that their lease agreements exempted them from such taxation as they had been made prior to this legislation being enacted. However, St. Louis County contended that these leases were subject to any changes in tax laws regardless of when they were signed. The court ruled in favor of St.Louis County stating that while contracts are protected under the constitution against legislative interference, it does not extend to exemption from taxation unless explicitly stated within an agreement or contract itself; which wasn't present in this case between Duluth & Iron Range Railroad Co and its lessors. This decision upheld states' rights to impose taxes on property despite existing contractual agreements and reinforced governments’ power over private contracts especially where public interest is concerned.

In the dissenting opinion for Duluth and Iron Range Railroad Company v. St. Louis County, Justice Harlan argued that the majority's decision was inconsistent with previous rulings of the Court regarding taxation laws. He contended that a state has no right to tax property located outside its jurisdiction, even if it is owned by a corporation operating within its borders. In this case, he believed Minnesota had overstepped its authority by taxing iron ore mined in Michigan but transported through Minnesota via railroad cars owned by a company based there. The justice insisted on maintaining clear boundaries between states' rights and federal powers when it comes to taxation matters; otherwise, he warned of potential conflicts among different jurisdictions leading to confusion and unfairness in implementing tax laws across states.