|Source: The Economist|
If the economy is to stay strong, then we need a lot of people to join the workforce to keep the dependency ratio favorable. Some of the new workers will be children born in America who grow up and go to work; it is important that these kids (white, black, brown or yellow; Anglo or Hispanic or whatever) be healthy and educated to fully participate in the jobs of the future.
As it stands, there probably will not be enough young American citizens to continue economic growth. Giving citizenship to undocumented people who are already here would help build the workforce, especially the kids, and especially if those kids too are healthy and well educated.
We will also need a better immigration policy. There are a lot of people who would love to come to the United States, join our workforce and contribute to our economy. Building walls along the border won't build the workforce needed in future decades. A well designed immigration policy would help achieve that purpose!