Here is how to get Mexico to help build the wall. Every illegal alien caught will be sentenced to 5 years hard labor building the wall, and immediately deported afterwards. When the word gets out, they won’t dare try to come here illegally.
Setup outdoor prison camps near the border like Sheriff Joe did. Any illegal that is deported and is caught returning should be imprisoned there for 2 years and then deported again. 10 years for the next offense. This shut would stop immediately!