No matter how deep, how tall, or how wide a physical wall may be, it is not going to stop aliens crossing into America.
However, a simple card that will fit into your pocket or around your neck will: just as driving on America’s roadways is a privilege and not a right, so to is access to its retail services. And once everyone is issued a REAL ID, access to these retail services will eventually be tightly controlled.
Everyone will be caused by law to have and carry at all times their personal card. So that, before someone is allowed to complete a purchase at McDonald’s, Wal Mart, Sears, 7-11, cable TV, water co., telephone co., etc, they must show they have that privilege by scanning their REAL I.D. card. Fraud will be impossible because they must also submit to an eye and/or finger print scan also.
Voila! A perfect wall. Prevented from purchasing gas, food, or lodging, they will then choose on their own not to enter or to stay within America.
Other uses would prevent someone wanted by the police, refusing to pay taxes, refusing to pay child support, and others from purchasing gas, food, or lodging as well.
It will create a permanent record of all purchases made by every individual that will be invaluable to crime investigators, the I.R.S. and others in authority.
It is a REAL win, win, win system for a safe and secure future.