In the case of Toltec Ranch Company v. Cook in 1903, the United States Supreme Court addressed a dispute over land ownership in Arizona. The Toltec Ranch Company claimed that it had purchased lands from an individual who had received them as part of a Mexican land grant before Arizona became part of the U.S., and thus they were exempt from federal public domain laws. However, William H. Cook argued that he was entitled to some parts of this land under U.S law because he had made improvements on it while believing it was public domain property available for homesteading or purchase. The court ruled against Toltec Ranch Company, stating that their claim based on pre-existing Mexican grants did not hold up since these grants were never confirmed by Congress after Arizona's acquisition by the U.S., which is required under American law for such claims to be valid. Therefore, these lands remained part of federal public domain and subject to its laws. This decision upheld previous rulings establishing that all unconfirmed Mexican land grants are considered void once territory becomes part of America unless explicitly recognized by Congress - reinforcing national sovereignty over territorial acquisitions.

The dissenting opinion in the case of Toltec Ranch Company v. Cook argued that the majority's decision was incorrect because it failed to properly interpret and apply Arizona law. The dissent believed that under Arizona law, a mortgagee has an absolute right to possession of mortgaged property after default and foreclosure, regardless of whether or not they have obtained a formal legal judgment against the mortgagor. Therefore, according to this view, Toltec Ranch Company should have been allowed immediate possession of the disputed land following their successful foreclosure action against Cook. This interpretation would uphold creditors' rights and ensure consistency with established state laws regarding real estate transactions.