Concern about the political proclivities of newcomers has, for good and ill, been a recurring feature of immigration debates in this country going back to the Founding. Because our national identity has a strong political component, we think that we can absorb people from every nation; they need only convert to the American creed. But for the same reason, our political debate often turns on disagreements about what that creed means, and so the partisan effects of immigration acquire greater significance. “Separating” these issues seems impossible.
It would be good for the debate if a conservative who favors higher levels of immigration were to write a serious book on the subject: one that treats restrictionists and their legitimate concerns fairly, that assesses the empirical matters involved honestly rather than propagandistically, that moves beyond talking points. I haven’t seen any recent book that meets this description (and I have skimmed Riley’s).
Update: Reader J.V. suggests Michael Barone’s The New Americans.