What we had was really REALLY good fencing in heavily traveled areas and progressively weaker fencing out in the boondocks. The main reason is that if it takes 2 hours of driving over rough terrain to get around a fence, mostly they would just skip that and bring some ladders and climbing equipment for the existing fence near the road. It only takes a few minutes to climb a fence, no reason to drive 4 hours to go around, and gas is expensive! There is a point where the hassle factor of reaching an area is more of a deterrent than a fence. Also we had other means of watching travel in the boondocks and all fencing still has to be backed up by border patrol feet on the ground since all fences are climbable. Fencing also requires constant maintenance and there is a point where the cost of trying to maintain fencing out in the boondocks where immigrants almost never travel when the area is already been monitored anyway and there is already border patrol in the area, becomes just not worth it, because fencing is not a magic fixall. That is why we never had fencing all the way across the border, the value was not worth the cost. It's the same reason we don't try to fence the ocean. The money spent would be more effectively used in other areas.

But Trump made a big show of pretending there was not already 700 miles of fencing and bragging about building a 'wall'. It was a political ploy the whole time. Then the Dems pretended that there was not already 700 miles of fencing and said that fences were bad, which is equally stupid. The fact is that upgrading fencing out in the middle of fucking nowhere where no one ever goes was never going to do much. The majority of immigrants come in through the asylum system or with tourist visas and then overstay them. And the drug runners can easily afford equipment to remove or get over or under fencing. Sometimes they also just catapult bundles over the fence to be picked up by someone else on the other side. THe biggest prob they have is the border patrol, not a fence.