Since it is very much not in interest of those who run Mexico to have the United States act to rebalance the labor cost component of cross-border products, I've been expecting the NAFTA renegotiations to quietly include a Mexican government commitment to closing its border – something it would presumably have to use its army to do.  However, a better option may exist.

The land border is about 1,989 miles long, but a highway along its length would be a bit longer – about 2,100 miles. In round numbers, a 2,100-mile interstate-class highway built along the Mexican border using products and labor sourced from both sides of the border should run well under $40 billion if it has 96 exchanges (to accommodate all 48 official crossings); continuous, full coverage; and electronic monitoring.  The cost includes ten entirely new state-run air national guard stations for VTOL aircraft set 50 miles or so inland.

Again in rough numbers, maintenance and operations for all of this would come to something under twelve billion a year – including a number of new border patrol stations along the highway.

Every inch of this highway, roughly 300 feet across and 2,100 miles long, would be under continuous surveillance.  No part would be more than five minutes from a monitor drone, no part would be more than 15 minutes from a border patrol team, and no part would be more than a 30-minute flight for even something as slow as a 1960s troop carrier – the CH-47.

The highway would bring enormous economic change to both sides of the border – and because no engineer could look at the map without wanting to put part of the highway south of the border, getting it built that way provides an unparalleled opportunity for a long-term co-operative effort addressing a wide range of social, economic, and political problems with one solution.

Bottom line?  A modern interstate makes a better wall: it's wildly positive instead of negative; the two countries get a new transcontinental highway instead of an embarrassing white elephant that will eventually have to be removed; Mexico pays part of the cost; both sides benefit; the wetback phenomenon recedes into history; the drug gangs on both sides of the border get brought under control; and four national guard organizations, including those in Texas and California, get the tools and practice they need to develop as quick reaction forces in the event of the more common types of larger-scale terrorist attacks.