Well, we don't need to import them. We have about 180 thousand of them here. They speak English, and if they can buy more land their numbers will increase to the point where where our population will be stable without immigration.
We are not Europe, and we are not a South American country. We have plenty of fundamentalist Christians who are willing to do hard work. We don't "need" illegal aliens any more than we need heroin or cocaine. There may be a lot of people willing to pay for illegal commodities but that does not mean we "need" them.
If there are 10 mil illegals, I fail to see how 180 thousand could be of any consequence.