Do you really think a wall will keep out illegals?
All illegals? Nope, but would it prevent many? Absolutely.
Combine, the fence with other efforts, such as:
(1) eVerify, strict enforcement and swift penalties against employer.
(2) Denial of Medical, Free Educational and Public Assistance services for people in this country illegal.
(3) 1st offense deportation, 2nd offense 5 year incarceration.
(4) Strict enforcement and swift penalties against landlords.
(5) National ID cards and officer checking proof of citizenship during traffic stops.
(6) End birthright citizenship
(7) Etc.
Combine the fence with some of these solutions and more and the illegal immigration problem would be a thing of the past!