In the case of Fond Du Lac County v. May in 1890, the U.S Supreme Court ruled on a dispute involving land ownership and taxation. The plaintiff, Fond du Lac County in Wisconsin, claimed that it had rightful ownership over certain lands due to tax delinquency by previous owners. However, defendant George W. May argued that he was the legal owner of these lands as they were granted to him under an act of Congress which provided for "the sale of pine timber on public lands" in Minnesota and Wisconsin. The court held that while counties have authority to levy taxes on properties within their jurisdiction, this power does not extend to federal property unless explicitly authorized by Congress - even if such property is located within county boundaries. In this particular case, since there was no explicit Congressional authorization allowing Fond du Lac County to tax federally-owned timberlands at issue here; therefore its claim based upon alleged tax delinquencies was invalid. Furthermore, because Mr.May's title derived directly from a federal statute granting him rights over these specific parcels of land (which superseded any conflicting state or local laws), his claim prevailed over that made by the county.

The dissenting opinion in the case of Fond Du Lac County v. May argued that the majority's decision was inconsistent with previous rulings and interpretations of law regarding taxation. The justice disagreed with the majority's view that a state could not tax Indian lands held under federal trust, arguing instead that such lands were subject to state jurisdiction unless explicitly exempted by Congress. He contended that this interpretation had been upheld in numerous prior cases and should be maintained for consistency and fairness. Furthermore, he expressed concern about potential negative implications of allowing federally-held land to escape local taxation, including possible financial burdens on states or counties where large amounts of such land are located.