“Sounds like you plan on having a military force there anyway. If so, then why do you need a fence? Why pay the huge cost of building it when Perrys plan is the only thing that actually will work?”
No, you also need a wall that makes for GOOD Neighbors.
In essence, we already do have a “wall”. It's called “Desert” for 30 miles either side of the border. Take out the “watering” stations, phone booths, sleeping stations, marked trails and all the other coddling measures taken to help them cross and the story would quickly change. In addition to that, make them spend hard time in jail for the first offense, and then make it a felony and prison time for repeated offenders.
Perry would have no problem enforcing just that.