In Leahy v. State Treasurer of Oklahoma et al., the U.S. Supreme Court ruled on a dispute involving oil and gas leases on restricted Indian lands in Oklahoma. The case was brought by John F. Leahy, who had purchased such leases from an Indian allottee but later discovered that the state treasurer had sold them to another party at public auction due to unpaid taxes owed by the original allottee. Leahy argued that these sales were invalid because they violated federal laws protecting Indian property rights. The court sided with Leahy, holding that under federal law, restricted Indian lands could not be subjected to state taxation without explicit Congressional authorization - which did not exist in this case. Therefore, any tax sale conducted by the state based on such unauthorized taxation was void and conferred no title upon its purchaser. This decision reinforced protections for Native American land rights against encroachment by states seeking revenue through taxation or other means without clear legal authority from Congress.

In the dissenting opinion for Leahy v. State Treasurer of Oklahoma, it was argued that the majority's decision to uphold a state law taxing intangible property held by non-residents violated both due process and equal protection clauses of the Fourteenth Amendment. The dissenting justices believed that this tax unfairly targeted out-of-state bondholders while exempting in-state residents from similar taxation on their intangible properties. They also pointed out inconsistencies in how such taxes were applied, with some non-resident owners being taxed while others were not based on arbitrary factors like whether they had ever physically possessed their bonds within Oklahoma or if they used an in-state trustee to manage them. This inconsistency further underscored what they saw as a violation of equal protection under the law.