If Trump is going to build his wall he will need to
"TAKE" hundreds of miles of land.
In the process Trump will also cut people off from 1000's of acres of farm / range lands they will still own.
If that doesn't sound fair well the President needs to fulfill his promise and the only way is to
"TAKE" land from people who own it.
Eminent domain, the big-government tactic Trump needs to build the wall, explained - Vox
The process by which the government can take private land to use it for public purposes is fairly straightforward.
Lawrence Tribe, a professor of constitutional law at Harvard Law School, says a private landowner is approached by a government agency that wants their land, that agency “typically gives them a deadline by which they must either sell the designated parcel of land to the federal government at the price offered by the government, or have it involuntarily taken by eminent domain at fair market value.” On the border, that agency might be the Department of Defense, the Corps of Engineers, or the Federal Emergency Management Agency.