The example of the Guatemalan DOAN (and of more recent Mexican police reform efforts) demonstrates that even a competent, well-paid and well-equipped police institution cannot stand alone within a culture that is not prepared to support it and keep it clean. In other words, over time, an institution will take on the characteristics of, and essentially reflect, the environment surrounding it.
As unlikely as it is to happen, the solution for now seems to be to protect the United States as best as possible from the violence that has taken over northern Mexico's hinterlands, whether by constructing more walls, setting up more armed forces, or something else. The situation strikes me as being much like that between Israel and the Palestinian territory. I very much agree with Israel's construction of the security walls (recognizing that I am in the minority on that, usually) and from day one I've been in favor of the walls along the southern US border. Like Robert Frost said, good fences make good neighbors.
Human permeability is behind institutional permeability, despite our efforts in the US to give institutions a life of their own through legal definitions and court decisions. I think this environmental effect goes through every area, every level of life. As I've posted on Facebook before, if you want to change your life, you have to change your values. This is way more complicated than blithely observing, "Do what you always did, get what you always got." The latter is so easy that it's dismissive. Changing values is some of the hardest work anyone will do. If it's that difficult on a personal level, then how much more difficult must it be on the national and international level? People rail about incremental change, but frankly, I don't see any other way that change can happen. So for now, I approve of the walls, the increased numbers of guns and agents, and the heightened awareness being used along the US-Mexico border.