Is that the one that allows the feds to own certain land, but not other land?
Amendment 10
"The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people."
Article I, Section 8
"The Congress shall have Power To ... " Then follows activities authorized, none of which includes holding ownership, dominion, and control, over vast stretches of land. It makes allowance for post offices, dockyards, arsenals, and other needful buildings, but makes no mention of vast stretches of land not necessary for the placing of said structures.
