Giving Compass' Take:

• Raphael S. Cohen explains that border walls can prove to be an effective short-term tactic, but not a long-term strategy. 

• How can funders work to resolve border issues in the long-term? 

• Learn how to build immigration consensus in a divided world. 

President Trump has claimed a wall would be “99.9 percent” effective at stopping illegal immigration while leading Democrats argue a border wall is unnecessary and would be “ineffective.” And so it may be worth stepping back from the politics of the day to view walls in their historical context. After all, states have been building walls since ancient times. Some were arguably quite successful, others less so. At the core of prudent policy lies a basic question: What can walls realistically accomplish?

Walls do work, at least for a time. There is a reason, after all, why states across the centuries have turned to walls as solutions to strategic quagmires. As mentioned before, walls have proven notably effective in places like Iraq in tamping down violence. That said, walls also have a shelf-life. In military parlance, walls are delaying obstacles. But no historical wall has proven impregnable.

Partly because walls are only a delaying obstacle, building them is only half the issue. After their construction, they need to be constantly monitored—often the harder task, even with advanced technology. In this sense, the Israeli effort around Gaza is particularly instructive. The Israeli-Gaza border after all is comparatively tiny, about 60 kilometers or less than a fiftieth the length of United States-Mexican border, and the Israelis still need to devote ample technological resources and manpower to watching it. And even so, these walls have not been foolproof.

Walls sometimes can create new ethical dilemmas. Walls can become the focal point for conflict. A recent example of this occurred when Palestinians—some of them armed—protested near the Gaza wall for seven months beginning in March. While accounts vary, human rights groups place the number of casualties at over 5,800 injured and 180 killed. Even in less extreme cases, walls—especially in populated areas—may disrupt trade and the free flow of people, inflicting a cost on the local population.

Finally, walls are a tactic (if, at times, a critical one), but ultimately, not a strategy.

Read the full article about border walls by Raphael S. Cohen at Rand Corporation.