Years ago, probably around the 1980s, when I first started paying attention to the illegal immigrant issue, the term "pressure valve" was in fairly common use. Meaning that illegal immigration to the US was a pressure valve to prevent any serious build-up of social unrest or revolution in the Latino nations from Mexico on southward.
Rarely see "pressure valve" any more as it's now politically incorrect..
They also use us as an ATM. Pulling billions out of this nations economy all the while getting free health care and free education.
Human garbage.