A lot of people who I think don't genuinely believe that the interests of foreigners should play no role in our thinking about immigration policy at least claim to believe that during Twitter conversations. But I defy you to look at Vlad Sokhin's photos of children sold into slavery in Haiti and think to yourself: "Well, this doesn't matter. They're foreign." Of course the child slaves in question are not called slaves; they're called restaveks (derived from the French rester avec meaning "to stay with"). NGO advocates estimate that there are 250,000 of them—"children working as unpaid domestic servants after their parents, who cannot afford to raise them, give them away."
If you could do something to improve the lives of these children and of the parents who feel that this is their best choice, you would, right?
There's probably more than one thing we could do as a country to help desperately poor Haitians, but it turns out that one of the most effective ways to help a Haitian is to let the Haitian in question move to the United States of America. Michael Clemens and Claudio E. Montenegro have calculated that a Haitian worker can typically increase his wages sevenfold by moving to the United States. Most people are moderately reluctant to leave their homes and families and uproot themselves to go to new country, but I think just about anyone facing severe economic stress would move to the U.S. before turning their own kids into slaves. And the option to exit would not only improve the lives of those Haitians who took advantage of it. It would also force members of the Haitian elite who want domestic servants to offer a more attractive proposition than "give me your child as a source of unpaid labor." Domestic workers in the United States do not enjoy high wages and are not especially well-treated, but as this restavek story emphasizes life at the true subsistence frontier is much much worse.
And best of all, letting Haitians move here to work is something we can do at essentially no cost to ourselves. If the concern is that an influx of poor workers will add to the long-term burden of paying for retirement programs for senior citizens, then specifically address that and don't let people move here permanently and retire. Let a worker come and work here for a spell of years, increasing his or her wages massively and slightly increasing average American incomes, and then have the worker move back to Haiti with his nest egg.