NavyCanDo wrote above:
"...Not to mention all the privately owned land that would have to be bought up."
I sense that many, perhaps most, perhaps nearly ALL of the landowners on the border would gladly give up the small area of their land on the border for that wall.
They are among the most put-upon by the hordes coming across now.
By the way, Rick Perry's comment on this is so asinine that it illustrates succinctly why his "candidacy" ended so quickly. The guy's a dolt.