“I got news, a wall is temporary, too. First rule of defensive obstacles is that they’re useless without overwatch. If this POTUS or future ones decide not to enforce real border security anymore (i.e. Border Patrol actually on the ground), then it’s just a thing to tunnel under or climb over or even knock down.”
In ancient times, the amount of money allocated for a standing army rose and fell, depending on the seasons, but a wall, once built, was there as a permanent barrier to adversaries looking to get at the riches within. It needed to be defended, but could be held at far less cost than open country. In the modern era, a defensive trench, like other fortifications, cannot prevent a superior enemy from advancing. But it can greatly raise to cost of that advance to that enemy.
Obstacles, in order to be effective, need overwatch. Otherwise they’re annoying speed bumps.
Imagine stringing concertina wire across a road. Triple-strand, reinforced with pickets—the works. Now, everyone pulls back due to...I don’t know, budget cuts. When the enemy infantry hits the wire obstacle, what happens? Nothing. They break out their wire cutting tools, reduce it and move on. It added a few minutes to their trip, but that’s it.
Now instead of pulling back, imagine placing an Infantry platoon with its machine gun teams and M203s and frags and whatever else in prepared positions overlooking the wire obstacle. What happens to the enemy infantry?
I agree that a wall can help canalize the illegals, but unless follow-on admins commit to the necessary personnel to man the thing, it’s not going to do a whole lot of good. A wall is certainly better than no wall, but too many keep talking like a wall is THE solution rather than a part of one.