Stephen Johnson Field,
Marsh v. Nichols Shepherd Company…
“ With respect to patents for land, we have had frequent occasion to assert their inviolability against collateral attack, where the land department had jurisdiction, and the land formed part of the public domain, and the law provided for their sale. But we have also held that if the land patented was never the property of the United States, or had been previously sold, or reserved for sale, or the officers had no authority to execute the instrument, the fact could be shown in any action or proceeding whenever the patent is offered in evidence. ”
