Trump risking war with Mexico for useless wall?

The planned meeting in Washington between President Trump and his Mexican counterpart, Enrique Peña Nieto, was called off after Trump signed his Jan. 25 executive order decreeing construction of a wall on the border—accompanied with more bluster about how Mexico will pay for it. Since the cancelation, Trump and Peña Nieto have engaged in an unseemly Twitter war, each taking responsibility for calling off the meeting. Things got worse when the White House raised the option of making Mexico pay for the wall with a 20% tariff on all goods coming in from our southern neighbor. The threat portends a trade war with the United States' third biggest trading partner.

Mexico's ex-president Vicente Fox jumped into the fray, tweeting of Trump: "We cannot cower before this dude even if he is a white guy, a strongman." He called Trump a "bully and a bluff," and has repeated over and over that "We will not pay for that #FuckingWall." In an interview with CNN, Fox even said Trump reminded him of Adolf Hitler.

That the Mexicans were expecting trouble is evidenced by the surprise extradition of top drug lord Joaquín "El Chapo" Guzmán to the US on Barack Obama's very last day in office. As Trump was being sworn in on the Capitol steps on Jan. 20, Chapo was being arraigned in federal courtin Brooklyn, pleading not guilty to charges of overseeing the smuggling of some 200 tons of cocaine into the US. It smells very much like Peña Nieto didn’t want Trump getting the credit for bringing in Chapo—and wasn't sure of continued cooperation between the two countries' bureaucracies.

Many have pointed out how futile Trump’s proposed wall would be—"inútil" (useless) being the favored word in the Mexican press.

For starters, illegal immigration into the US from Mexico is now at a 20-year low—there has actually been a net reduction in Mexican immigrants, with more returning home to Mexico than entering the US since the 2009 Great Recession, according to a study by the Pew Research Center.

And as for keeping out drugs, Trump's other justification for the wall? A BBC fact-sheet on the question points out that according to a 2015 DEA "National Drug Threat Assessment" (online as a PDF), the bulk of illegal narcotics enter the US through border checkpoints and points of entry, hidden among more than 5.5 million commercial trucks that cross the border each year. (Similarly, most Mexicans who are in the US illegally entered through legal means and then overstayed their visas.)

And even for those drugs that do now come in through remote desert stretches where there is no checkpoint—the wall would still be pretty pointless. "Trump's wall would not have any impact on the movement of drugs through the US-Mexico border," Mike Vigil, a retired DEA agent who spent time undercover in Mexico and Colombia, told Business Insider. "The Mexican drug traffickers would punch a hole through it, fly over it. They would be able to circumvent that with medieval technology, catapults, shooting stuff across the wall."

And indeed, the smugglers have already started using such improvised technology.

And there's the old joke about how a 20-foot wall would just create a market for 25-foot ladders. "You'd need to get rid of all the ladders in Mexico," a veteran US border agent told the