… is from page 209 of GMU Econ alums Alex Nowrasteh’s and Benjamin Powell’s superb 2021 book, Wretched Refuse? (footnotes deleted; links added; emphasis added):
Across the world today, support for welfare, redistribution, and government provision of public goods is inversely correlated with the share of the population that is foreign born and diverse. Besides allowing for mass unionization, closing the border also allowed the government to create a large welfare state while avoiding a powerful political counterargument: Immigrants are going to come here to take advantage of these benefits. Consequently, American progressives and other supporters of a large welfare state were near-uniformly against continuing the system of open immigration.