The myth persists that if the illegals who do the cheap jobs are kept out, a decent wage will have to be paid to Americans to do those jobs. The increased wages push the jobs AND the factories offshore. Clothing, appliances, etc. that used to be made at home are now made in South Korea, Thailand, Bangladesh.
The illegals obtain the rights of citizens either legally or illegally, but benefit our economy and contribute their share of taxes.
Factories that remain here pay American taxes and otherwise benefit the country.
To add slightly to Bobert's post, Hispanics are 30% or so of the population in California, Arizona, New Mexico and Texas. I believe, but haven't checked lately, that 10% of Chicago and 20% of Denver residents are Hispanic. New York? People with a common culture and a common language help each other, and the migrants blend in. Hispanics are an increasing part of the American fabric and this trend is bound to continue and increase.