Ok I can't take this anymore. The 5 generations after the founding fathers also had a preference for white northern Europeans. Your pie in the sky economic views are what an economic majors dreams are made of. Employers love immigration because it cheapens the cost of labor. Numbers aren't bad but when cheap goods or cheap labor enter a complicated workforce it hurts workers. When the labor market is low it drives wages up because your labor is worth more. People have children, reasonable immigration takes place. Bigger projects and companies grow from bigger numbers, but it is slow and makes progress. These people are economic invaders because the steal jobs from the poorest people then we have to care for both parties through welfare and handouts. They also cause wages to decrease.
Also since not everything comes to economics what of culture? Assimilation is key here my friend. See in past generations people eventually belly up and assimilate. You know why? Geography, the ocean is a barrier where you don't return home. You become part of the land. With our friends south of the border they are sucking money and sending it down south. They do not intend to become Americans. Just as Texans did to mexico so many years ago. They think this is ultimately their land. No it is time for them to go. They don't want to become Americans. They are economic raiders and vampires.