In all my days, I've seldom heard such non-sense as coming from the anti-wall/pro-illegal people. The wall is intended to dramatically SLOW the tsunami of people. It would be nice if it could totally stop the illegals, but that's, of course, impossible.
People who say the wall will never work, is like saying since we can never stop bank robbers, we should do nothing to slow them down. Nonsense, I say. Banks have dozens of anti-robber technologies. Bullitt-proof glass, exploding dye packs, silent alarms, armed guards, cameras etc, etc.
The same philosophy applies to hardening our borders. Stronger, taller walls, razor-wire, infra-red cameras, thousands of new border guards, drones, Natl Guard watchers, high-tech devices to detect tunneling, U.S. Coast Guard to watch for and catch drug smugglers/illegals, and other secret technologies.
Additionally, there are hundreds of check points scattered along our interior highways, Immigration and customs Enforcement (I.C.E), raids on work places.
Already there are new and tougher laws to punish repeat offenders. We are now separating children from their parents and placing the children in safe, comfortable shelters, while the parents are housed in special detention facilities without any possibility of "bonding out". As word begins to spread, fewer and fewer even attempt to cross illegally
There may not be any perfect solution but every little bit helps.
What we CAN NOT do is post "WELCOME" signs that say, Come one, come all. No limits.