A Lesson from the Past Regarding Illegal Aliens?

When Columbus returned to Spain, he had heard that the Pacific Coast had  unlimited gold reserves that could easily be dug up with a shovel. Miscreants,  the unsuccessful, highway robbers, etc fought for a spot on the crew of the ship  that the Crown was sending to find it. On arrival, they found no gold awaiting and robbed and/or murdered the natives. 

I believe there's significant chance this will occur here. Well-meaning but foolish Americans will hand over California, maybe even the whole country (whose wealth and scientific discoveries have benefited the world) to the illegals and their advocates, as in the Columbian example, people who disproportionately were failures or criminals in their home country. 

When they take over, my intuition is that they'll treat us far less kindly than we've treated them. And a look at all the countries in Central and South America doesn't make me optimistic that a U.S. under the illegals' control will be a better America.