I doubt it would be devastating. America had a strong economy long before the massive immigration of the 1990s. The region I'm in has extremely high immigration and the highest poverty rates of the USA --- also very high unemployment and welfare rates. Even states like Michigan have high unemploymnet rates --- something over 7% --- you'd find workers if you paid more than $3-4 an hour and maybe offered a little health insurance for those jobs.
We are rakin the bottom. We have welders making 5.50.
Our young people cannot survive here unless they work for daddy.
The people farming, and ranching cannot compete with the big corporate operations without low wages.
The Kids must go somewhere else and the only way to fill those jobs is with migrant labor, as they have done for a hundred years.
There is some industry in the north west parts, but they are going fast. Levis is gone, all the textiles have folded and whirlpool is going to Mexico.
The largest employer in most towns are the social services. The states largest employer is the state, and more than 50% of the population is on assistance and below the poverty line.
Ya want some! And you thought Huckabee was having fun!