In the Mills v. United States case of 1896, the Supreme Court ruled on a matter concerning land patents and mining claims. The plaintiff, Mills, had purchased land from an individual who had obtained it through a patent issued by the U.S government under mining laws. Later on, another party claimed that they owned part of this property due to their pre-existing quartz mine located within its boundaries. This claim was based on an act passed in 1866 which allowed individuals to stake out mineral-rich lands for personal use before these were officially surveyed or sold by the government. The court held that while such rights could be established over unsurveyed public lands if minerals were discovered thereon prior to any official surveying or selling activity by the government; once such lands have been officially patented and transferred into private ownership without reservation of any kind - as was done in this case - then all subsequent claims are nullified unless specifically recognized in said patent's text. Therefore, since no mention was made about preserving existing miners' rights when transferring title via patent from public domain into private hands here; nor did defendant prove his alleged discovery predates said transfer: he has no valid claim against plaintiff's current ownership status per se.

In the dissenting opinion for Mills v. United States, Justice Harlan argued that the majority's decision to uphold a tax on income from property was unconstitutional. He contended that such a tax is essentially a direct tax and therefore must be apportioned among states according to their population as required by Article I, Section 9 of the Constitution. The majority had ruled this was an indirect or excise tax which did not need apportionment but Harlan disagreed, stating it directly impacted property owners' wealth and thus should be considered direct taxation. Furthermore, he expressed concern about potential abuse of power by Congress if they were allowed to impose taxes without regard for constitutional restrictions like apportionment rules.