I believe that once asylum is granted in the US, it's permanent. And, yeah, getting rid of the black market for drugs would go a long way to fixing a lot of problems.
A country is not a property like a home. No person or collective owns the United States. Furthermore, a lot of the illegal immigrants do ask permission from the federal government, they simply get rejected. Moreover, there are plenty of American residents and citizens who welcome the Mexican immigrants, so there are already plenty of people who have just as legitimate a claim to the US as "home" as you or I welcoming these immigrants, both legal and illegal.
There's plenty of room for debate and discussion as to what extent the federal government can be considered a steward, an owner or merely a servant regarding the nation as a whole and furthermore public property. Consider it this way, the government being able to dictate what guests I have in my home because they are illegal immigrants is a violation of my property rights.
Potential, even active, competition for resources is not harmful. Refusing to share an abundance of resources with the needy is causing harm. How needy Mexicans and immigrants are, I can't say. Nor do I know if the US as a whole is facing a resource shortage. I strongly doubt immigration is a major contributor to any water shortages. And even so, better that we open the border and use the influx of labour to improve our ailing infrastructure. Because, frankly, one of the biggest reasons why illegal immigration is large is because cheap labour is one resource that seems quite scarce in the native population.
Thanks for the discussion.