Us Iowans love it when Uncle Sam gets his hands on our fields to build a Pentagon on top of.
If you need land to build a new capital, ask states to donate land, like what Maryland and Virginia did on the Potomac. If this goes to referendum, the only people who should be allowed to vote should be Iowans, Missourians, and Illinoisans, as I don't know why someone from California or New York has a stake in it. I also assume plenty of civilians who live in Nyman, Central Maryland, and Northern Virginia would also oppose this law taking countless jobs away from the area, forcing those employed by the federal government and their families to move halfway across a continent because of "national unity" or something.
It's a cute idea, and it's something I've actually brought up in the past, but ultimately, the physical location of Nyman isn't a problem. So why fix it, and why do so in a way that infringes on the domain of three already existing states, one of which I hold very dear to my heart?