Angelo Codevilla, a Boston University professor of international relations, and I have been engaged in a back-and-forth on the need for (or futility of) border enforcement:
His article which got the whole thing started ran in the Claremont Review of Books entitled "Our Borders, Ourselves".
My initial response, at National Review Online, is here.
His second shot, also at NRO, is here.
My lengthy second shot, posted today, is here. Comments can be posted at NRO.