HONOLULU • Call this the Year of Border Walls. In 2015, Estonia, Hungary, Kenya, Saudi Arabia and Tunisia all announced or began the construction of barriers on their frontiers. We may live in an era of globalisation, but much of the world is increasingly focused on limiting the free movement of people.
At the end of World War II, there were only five border walls around the world. Today, according to Ms Elisabeth Vallet of the University of Quebec in Montreal, Canada, there are 65, three-quarters of them built in the past 20 years. And in the United States, Republican presidential candidates are promising more. Republican front runner Donald Trump has repeatedly proposed building a wall along the entire border with Mexico. And on a talk show, another Republican candidate, who has now quit the presidential race, Wisconsin Governor Scott Walker, described building a wall on the US-Canada border as "a legitimate issue for us to look at".
And yet existing border walls are neither cheap nor effective. Israel's wall in the West Bank cost more than US$1 million (S$1.4 million) per 1.6km to construct. According to US Customs and Border Protection, building and maintaining the existing 1,080km of border fencing on the US-Mexico border would cost US$6.5 billion over the barrier's expected 20-year life cycle. At this price, fortifying the remaining 2,090km of the Mexico border would cost more than US$12.6 billion. Erecting a wall along the 8,900km border with Canada would cost almost US$50 billion and would cut through an airport runway, an opera house, homes, and businesses that straddle the border.
Nor is there much evidence that border walls work as intended. To be sure, prisons demonstrate that short, well-guarded walls can be extremely effective at preventing movement. But even prison walls are only as effective as the guards who ensure that they are not breached, and guards can be susceptible to bribes.
The recent escape of the drug cartel leader Joaquin "El Chapo" Guzman from a Mexican prison highlights another vulnerability of border walls: tunnels. Since 1990, the US Border Patrol has found 150 tunnels beneath the US-Mexico border. Those with money will always be able to cross borders using fake documents, bribes or innovative infrastructure.
Indeed, fortified frontiers are most effective at stopping poor migrants and refugees. And even then, rather than preventing migrants from entering, fortifications all too often funnel them towards more dangerous crossing points. The result is a mounting toll of predictable deaths. The International Organisation for Migration estimates that from 2005 to last year, 40,000 people died attempting to cross a border.
Unlike prison perimeters, borders can be thousands of kilometres long, which makes them difficult to monitor properly. The US employs more than 20,000 Border Patrol agents. But even if they were all on duty at the same time, each would need to guard a 520m section of the border.
Of course, equipment such as cameras, motion sensors, drones, helicopters and vehicles allow agents to watch long sections of the border. But the necessity of monitoring border walls points to one of the fundamental truths about them: Historically, most have proved to be pretty useless. The most famous sections of the Great Wall of China were overrun within a few decades of their construction. When Germany invaded France in World War II, it simply went around the Maginot Line. The Berlin Wall fell within 30 years of its construction.
Indeed, border guards and their equipment can be equally effective without a physical barrier. At best, walls and fences only slow people down, making them a poor investment from a security standpoint. They are similarly ineffective from a military perspective. Missiles and airplanes can fly over them, and tanks can smash through them.
And yet, despite their high cost and low efficacy, walls remain popular among policymakers and politicians. They provide imposingly tangible evidence that something is being done about migration. High-tech surveillance and boots on the ground may be more effective at preventing people from crossing a border, but a wall can be used as a political prop.
If Mr Trump ever builds his wall, he should build a really nice one, like the Great Wall of China. Then one day it might become a popular tourist attraction - and finally serve a useful purpose.
PROJECT SYNDICATE
•Reece Jones, a professor of geography at the University of Hawaii - Manoa, is the author of Border Walls: Security And The War On Terror In The United States, India, And Israel, and the forthcoming The Violence Of Borders.
