Illegal immigration has been a problem in America (and many other countries) for centuries. In what is now called the United States let's solve it by sending the children of illegal immigrants and the children's children, yea unto to the sixteenth generation, back where they came from. Let's start with sending all the Mayflower descendants back to England!
Did they really get permission from all the governments of the people already living here to stay put and to take resources from the then current occupants? Did they learn the customs and the languages of the people already living here? No, they insisted on following their Old World customs and speaking their Old World language. Even that language was a mishmash of the language of illegal immigrants from another part of the Old World.
Then let's send back all the children of the Southern planters and the children of their children. They grabbed great swaths of land from those already reaping the bounty of the land, they cleared the land of those pesky forests that produced an abundance of food, and they pushed those who already lived on the land farther and farther from the coasts.
And on and on it went, decade after decade, farther and farther west. Now the true illegal immigrants want to push out the descendants of the Anasazi, the Aztecs, the Toltecs, and the Mayans from land they had occupied for millennia until the real illegal immigrants arrived.
And we should send the Ojibwe out of the territory they took from the Dakota. And we should send the Lenni Lenape out of the territory they took from others as they pushed east to the Great Salt Sea (see James Fenimore Cooper).
If we all stayed put in the land of our fathers and their fathers, just think of how we could reduce the problem of illegal immigration!! Of course, if we all did that, we would still be peasants working from dawn to dusk, suffering cold and heat according to the season, and wondering when a drought or the foreign overlords would wipe us out.
We really should follow the advice of Rodney King, "Can't we all just get along?" That means we have to absorb people moving in and we have to be sensitive when we move into others' territory. And next year we will have world peace.
