Adn no one can show otherwise.
Eh, yeah, I do believe they did show otherwise, see below.
Because immigration is changing the lives of Americans, that's why.
Immigrants are lowering our wages in this country, they are taking American jobs that Americans should have, they are changing us to a bilingual country because they come here without knowing the language and expect us to cater to them instead of the other way around. They are earning American dollars here and sending it back over the border to spend over there.
Wages are a supply and demand process. The lower the supply and higher the demand, prices go up. The higher the supply and lower demand, prices go down.
We can't increase our wages when we have an endless supply of workers coming into this country.
It is within our borders. Movement of free labor does not mean totally unregulated labor. That's cheating the system. Freedom of labor within our borders is a conservative principle, not importing labor