I repeat, those who are identified and can get visas are the least of our worries. And those tunnels were from walls across town borders, not the trackless desert that is proposed now. Minimal but smart acoustic sensors would reveal all tunneling anyway.

But I agree that the war on drugs (as well as on prostitution) is a motivating issue. It causes there to be a huge profit motive. I go further, and suggest that the State governments grow, manufacture, and sell at a cut-rate price, all drugs to any adult. They could sell it for pennies on the current dollar, and still make profits enough to fund drug rehab for those who want it. After the panic, revolution, starvation, and cannibalism settled down in those countries currently supplying our drugs, the States could decriminalize small home production and sell yearly licenses by lottery for reputable local suppliers. This prevents smuggling, bootlegging, and pushing. Eventually we could remove all drug laws with no disruption.

But that won't happen because democrats and republicans won't vote for a libertarian (no matter how bad their candidate is, as shown in 2016), and libertarians won't vote for anything but a "perfect" libertarian. Incrementalism is working marvelously against us, so I can't figure out why we don't get it to work for us.