It could be said that a nation should have control over its borders, so that those who are not citizens or even possibly enemy agents could not easily cross into the United States, which certainly seems like a sensible position to have because we ought to know who it is that enters our nation, and we ought to make it our point that there are procedures in place that those who would like to come into our nation must adhere to.
In actuality, crossing over the border, especially the southern border of the United States, is something that literally millions upon millions of people have done over the decades, which would more than strongly imply that there are institutions that desire for those who are not legal immigrants to find a way into our nation, probably because they are people that can be exploited to the benefit of those entities. That said there are ways to still permit non-citizens to come here, which, while not as lucrative for those in the business of using illegal people, would probably still serve their purposes adequately.
That is the reality of why so many illicit immigrants are here, and the response in recent times has been a clarion call to "build the wall," and many billions have been spent and allocated to doing that very thing. The problem with this sort of mission is that physically building a wall that would serve its purpose exceedingly well isn't going to ever occur, because where there is a will, there is always going to be a way. After all, physical barriers can be dug under, gone through, and circumvented by going over, because every wall has vulnerabilities. Additionally, the wall would serve to disrupt migratory patterns, and in some places, because of the topography, it isn't really achievable in the building, so of.
In a state of technological superiority, one would think a far better solution to protect the border would be the sophisticated usage of technology, through all the abilities that we currently have, so utilized in conjunction with information of where and how previous border vulnerabilities have been exploited, which would serve well in reducing such from where it has been in the past to something far smaller. So too, a policy which permits "guest workers" to enter this country would take care of our labor needs for certain jobs that domestic workers do not desire to labor with. This, in sum, would serve to do a far better job of taking care of the issue without the actual need to build miles upon miles of a border fence, which would simply represent a challenge for those that desire to cross the border, but would not be enough to stem the tide, because without an effective and robust team of personnel and equipment monitoring and defending that wall, people would still find a way to cross.
In short, there needs to be a comprehensive response and competent strategy using all the arrows within our quiver to effectively reduce illicit immigrants from entering this nation, which could be readily achieved if led by those of superior strategic vision.