I know that it was a simplification. I was pointing out the results of trying that before. We have to make the same decision the Romans were faced with - republic or empire. There is no in between. At least none that I know of. I would prefer we remained a republic. It is one thing to send in the military to destroy. A republic can do this well. It is quite another to occupy land indefinately. That is the path to empire. (What are we STILL doing in Iraq?)
...I think we do use a lot of Mexicans in the border patrols. This of course is a classic notion from slave societies as Texas and Florida once were. What is more natural? They speak the language...
Have you heard of Aztlan? Mexicans on the border and within the border is a dangerous notion. Did you know that we almost annexed all of Mexico after the Mexican wars? It probably would have been better than what we have today.
...Rome did not fall because of the barbarians, it fell because it weakened it's currency as too much gold went to the Far East. One has to wonder about the long term drain on our economy from the drug trade. Over the long haul, even a fraction of one percent in a continuous loss can make or break an otherwise stable situation...
If I had to pick one cause for the fall of Rome, I wouldn't say gold or trade. I would choose the heavy and unequal tax policy that eliminated the once thriving middle class. All that were left were the wealthy and many many poor. The backbone of the society was gone.