I would surmise we could make jobs of cleaning up Detroit and other slums while feeding, clothing, and housing these able-bodied, unemployed people (whether illegals or not). I think there is more work to be done than we have people willing to do it.
This is part of the meme that there are jobs Americans won't do. And now there is a push to double the guest worker programs (temporary work visas) from 650,000 to 1.4 million to do jobs Americans can't do.
This analysis tests the often-made argument that immigrants do only jobs Americans don't want. If the argument is correct, there should be occupations comprised entirely or almost entirely of immigrants (legal and illegal). But Census Bureau data collected from 2009 to 2011, which allows for detailed analysis of all 472 separate occupations, shows that there were only a handful of majority-immigrant occupations. Thus, there really are no jobs that Americans won't do. Further, we estimated the share of occupations that are comprised of illegal immigrants, and found that there are no occupations in which the majority of workers are illegally in the country.
Of the 472 civilian occupations, only six are majority immigrant (legal and illegal). These six occupations account for 1 percent of the total U.S. workforce. Moreover, native-born Americans still comprise 46 percent of workers even in these occupations.
Many jobs often thought to be overwhelmingly immigrant (legal and illegal) are in fact majority native-born:
Maids and housekeepers: 51 percent native-born
Taxi drivers and chauffeurs: 58 percent native-born
Butchers and meat processors: 63 percent native-born
Grounds maintenance workers: 64 percent native-born
Construction laborers: 66 percent native-born
Porters, bellhops, and concierges: 72 percent native-born
Janitors: 73 percent native-born
There are 67 occupations in which 25 percent or more of workers are immigrants (legal and illegal). In these high-immigrant occupations, there are still 16.5 million natives accounting for one out of eight natives in the labor force.
High-immigrant occupations (25 percent or more immigrant) are primarily, but not exclusively, lower-wage jobs that require relatively little formal education.
Remember those long lines around the block when McDonalds announced they were hiring? Americans will do any work. They always have and always will.