"can't win, don't try" is the message now?
let's at least give it a try.
ireland and ulster had a different problem, and were trying to stop terrorists rather than waves of mass migration.
Just one terrorist making it across the border into ulster was a disaster.
I don't know what percentage of the illegals the wall will stop. Hopefully 100%, but let's say it's only 50%. As far as I'm concerned that's still a success: cutting the number of illegals crossing each year from 1 million to 0.5 million is a success.
and it's only part of the solution, along with deportations of existing illegals and strict enforcement at the employer level, making it much harder for illegals to work illegally. Part of the solution is that illegals who are unable to work will self-deport. It happened under Ike