What are you talking about? What's so expensive about a silly wall. Don't listen to the spin. In some places it can be bob wire. Other places chain link. Other tall corrugated metal like the Israelis are using. Don't kid yourself, we can build a wall, and if we wanted to we could pay illegals $6.25/hour to do it for us, which I happen to think is a good idea.
The main thing is to back it up with force. Not the threat of, but actual force, then the faucet will close. THEN the threat will start to be effective, but not until the peasants are shown who is boss.
My point is that the wall can stop the illegal migration, but cannot secure our major border cities from a terrorist attack with weapons of mass destruction. We need to think well into the future. A failure to do so invites something worse than 9-11.