I see by your statement that you should never climb into a paper bag, you won't find ever your way out.
It would be very easy to close our borders, even easier to drastically reduce the exodus.
Either you're blind to simple logic or you're one of those who can never ever say "Mr. President THIS IS WRONG". You people are EXACTLY like the suck-job clintonoids that fell prostrate before him at all costs.
The American Indians felt a similar pressure and were unable to resist, even after going to war. Some solution short of war is being sought.
The pressure heretofore insignificant must be relieved. The current initiative is to begin a dialogue to determine exactly how that can best be done. Nothing has been done except to begin the discourse.
Another alternative would be to annex all territory south to the Columbian border. That also would produce great and probably unaceptable change. It is however an alternative solution.