Building a wall will NEVER solve all illegal immigration, all it can do is put a bigger dent into it then that currently exists.Or perhaps because he is the most ill-informed POTUS in history who thinks very complex issues are easy to solve until he actually attempts to solve them
But what would be your approach, hey we can't stop all illegal immigration, so lets just stop trying altogether??
While we're at it, we cant stop all crime, so lets get rid of the police