If you believe that America should not secure her borders, and that people should be free to cross them essentially unchecked and with impunity, then we disagree — and I’d be delighted to discuss the matter with you sometime.
But if you believe that America should secure her borders, then I want to suggest three ways in which a physical border barrier is superior to the alternatives.
There are alternative forms of border security available, none of which, incidentally, are incompatible with a physical barrier. We can create a virtual barrier using modern technology, with drones and sensors and cameras and things like that, and we can increase staffing to have a greater police presence on the border. But a physical border barrier has symbolic, political, and functional advantages that those choices lack.
Symbolic
There is a loud minority voice in America calling for open borders, and offering so-called sanctuaries to people here illegally. At their most extreme, these voices are, essentially, calling for an end to the idea of citizenship; certainly they dismiss a unique American culture as either a fiction or a plague, and don’t consider unchecked immigration a threat. To put it mildly, America sends a mixed message to would-be illegal immigrants about how we view illegal entry.
A physical border barrier sends a clearer, less mixed message: it’s hard to mistake a fence or a wall for a welcome mat.
Political
A conspicuous feature of a physical barrier is that it’s static: it sits there and it functions. Yes, it has to be maintained, but a failure to maintain a physical barrier becomes evident fairly quickly. In contrast, drones not flying, cameras not being monitored, sensors not working or being ignored, all of these are inconspicuous failures of border security, none as visible and self-evident as a downed fence or a breached wall.
In a political climate where non-enforcement is the preferred strategy of one side, making that non-enforcement conspicuous helps keep everyone honest.
Functional
There is a very real practical advantage to a physical barrier, one that no other border security mechanism can match. Physical barriers are the only humane way of preventing illegal immigrants from actually setting foot on American soil. (There are inhumane ways of doing that, but they involve large scale and lethal armed confrontation at the border. No decent person should want that.)
Why is it important that illegal immigrants not set foot on American soil? Because our legal system, with its generous and somewhat dysfunctional asylum laws and with a court system seemingly eager to hamstring border enforcement, makes it very difficult to deal effectively with illegal immigrants once they are actually in the country. In particular, the new phenomenon of caravans of would-be illegal immigrants seeking to enter the country en masse, thereby overwhelming our immigration process, can be effectively and humanely dealt with by a physical barrier; it is hard to see what other mechanism might work to deter these organized assaults on our border.
Only a physical barrier humanely prevents the mass influx of illegal immigrants bent on exploiting our own legal system to secure entry.