The man in charge of the wall for now is John Kelly, the secretary of homeland security. Mr. Kelly does not think a wall alone is the best way to secure the homeland. He said at his confirmation hearing that a “physical barrier in and of itself will not do the job.” He added, “I believe the defense of the southwest border really starts about 1,500 miles south” — that is, in helping Central America tackle the root causes of drug smuggling and migration. Nor does he think that erecting a wall as Mr. Trump describes it is even possible. Speaking to the Senate Homeland Security Committee on Wednesday, he said, “It’s unlikely that we will build a wall or physical barrier from sea to shining sea.”
But Mr. Kelly is no longer an independent retired general. He is now on Team Trump, and no matter what obstacles are imposed by reality — by topography, by physics, by Congress and by the budget process — a big, beautiful wall is what the boss wants.
Customs and Border Protection specifications say the wall must be concrete or some other material, preferably about 30 feet high but no less than 18 feet, “physically imposing,” “aesthetically pleasing,” impervious to tunneling to a depth of six feet and tough enough to repel a sledgehammer, pickax, acetylene torch or similar tool for at least an hour.