The moral thing to do is hold Mexico to a quota ~ no more than X number ~ and enforce it.
At the moment they are demanding more immigrant spots than any other nation in history.
They do have a quota and we do hold them to it.
But that is only in regard to LEGAL immigration. Those people have to go through hell to get here and to get their papers in order. Those who get here illegally don't have to do anything other than steal someone else's ID and then go steal another job from Americans.