Donald Trump’s call for a wall along the whole 2,000-mile border with Mexico has gotten a lot of immigration hawks excited. I understand the emotional appeal of his proposal, but it addresses what is actually the least serious vulnerability in our immigration system.
Border infiltrators were indeed the main type of illegal immigrants for a long time. Estimates dating from the 1990s were that about 60 percent of the illegal population had jumped the border.
But since then our effort at the border really has improved. While the number of border agents and the miles and type of fencing are all still inadequate, not all the money we’ve spent there over the past two decades has been wasted. Border crossings really are way down. We’re much more able than we were before to patrol the border effectively, though we have an administration in Washington that often chooses not to do so, as we’ve seen with the ongoing surge of Central American teenagers and families into South Texas.
But even if we were to build a wall, and elect a president interested in using it to protect America’s sovereignty, we’d be missing most of the problem — because the majority of new illegal aliens are actually visa overstayers.