From Shika Dalmia's article in Reason:
Yes, every nation has the right to control its borders. But both liberal and illiberal immigration policies are consistent with that right. Precisely because there is something inherently arbitrary about where the line is set, lawmakers can’t maintain a posture of absolutist intransigence regardless of the ground-level response. Just as unduly high levels of taxation encourage tax evasion, unduly tight immigration restrictions encourage illegal border crossings—not to mention illegal hiring. The Competitive Enterprise Institute’s Alex Nowrasteh points out that conservatives would never make tax cutting conditional on first ending tax cheating. Yet they see no contradiction in demanding the erection of a Berlin Wall on the Rio Grande as a condition for immigration reform.