I think it's simple: there must be no illegal immigration. Attempts should be punishable on sight, and not for the purpose of "deterring" (because indeed they can't be deterred), but simply so they don't exist. One bullet each. There must be no condition whatsoever that illegal border crossing should be tolerated. If someone has a known, specific place to be deported to, deport them, if not, just let go of them without much fuss.<p>There is nothing wrong with asking people to follow legal paths of immigration. Immigration exists for the benefit of the host country, not for the benefit of the immigrant, it may be only a side consequence: the reason why we let some selected people in is that we believe (sometimes falsely, but that's our problem), that this will make us better off. Not to make them better off. If there is no benefit to be obtained for the host country, don't let them in.