The Declaration of Taking Act, passed during the Roosevelt Administration, when they were hot to emulate their fascist role models in Europe (in Roosevelt’s very first cabinet meeting, they distributed books by Giovanni Gentile, who was called “the Philosopher of Facism”, and ghostwrote some of Mussolinis works).
The Declaration of Taking Act allows the Executive Branch to seize private property the same day, simply by issuing a “Declaration of Taking”. Former owners can go to the courts to settle the amount of compensation, but construction can begin immediately, enforceable at the barrel of a (police) gun.
The Trump Administration has gone to great lengths to contact property owners long in advance, and prepare careful appraisals for value.
Of the approximately 400 private property owners impacted in the approximately 100 miles contracted for construction in the RGV, some unknown number have already settled.
In the first few months of the administration, explicit guidance was given to ensure that adequate funds were budgeted for compensation of landowners - one of the big lessons learned from the Bush-era program. The overall cost estimate for the border wall was raised by several billion dollars during that period (upgraded specifications for the barrier system were also contributors to that increase).
In the end however, the Federal Government (Executive Branch) can pull up with a construction crew, a border Patrol Officer, and a piece of paper, any day of the week, and get right to work.
Good luck with that Taking Act. What I seen posted here, and from article on the web is that this is going to the courts. Supposedly for years.
You might tweet that to President Trump.
Would save a lot of judiciary hassle.