All we need to do is get the taxpayer money to buy the land from all the current US landowners along the US / Mexican border (most who have owned the land for generations) for whatever easement we need - 1/2 mile or so along roughly 2000 miles (1000 sq miles of land). Then put up a huge fence, hire people to patrol it in the middle of the desert in the middle of nowhere 7x24x365 forever. Sounds like a great plan. Name me one other country that does this (no points for Israel since we pay for that one too).
Instead of Iraq we should have invaded Mexico, replaced their government and pumped all those trillions into rebuilding that economy into something where Mexicans wouldn't need to come to the US for a minimum wage job to keep their family in Mexico from starving to death. Then we wouldn't have drug gangs (who are powerful because they have money) slaughtering people all over the place. Then maybe I could retire to a nice place in Mexico with clean water, reliable power, and an internet connection.
Oh wait - trillions later and we can't do that in Iraq either... Nevermind.