Troops. Food. Medicine. Money. Solidarity.

So far, the American response to the tragedy in Haiti has been exactly what you'd expect, and in the immediate aftermath of the earthquake that ravaged the nation on Jan. 12, such rapid assistance is precisely what is needed. But over the long term, there is another step, one that may be less obvious or popular, that we must take. It would vastly improve the living standards of the Haitian people, and if we had taken it earlier, it could have lessened the death toll of the quake.

We must let more Haitians come here. In fact, it's time to consider an entire new class of immigration -- call it a "golden door" visa, to be issued in limited numbers to people from the poorest countries, such as Haiti. It could be permanent or temporary, but that's less important than its core purpose. Our immigration law has traditionally had three primary goals: reuniting families, supplying employers and protecting refugees. But part of America's greatness is that in letting people come, the nation has pursued a fourth, unwritten goal: extending opportunity to those born in places without it. A golden door visa would simply recognize in law what the United States has done since its founding.

No human act can blunt the force of an earthquake, but the Haitian people's profound loss was not fundamentally caused by movements of the Earth. The reason that tens of thousands of people are dying in Haiti is, put simply, because Haiti is poor. Poverty means shoddy construction materials, lax enforcement of building codes, abysmal emergency response and low stocks of food and medicine. The earthquake shook the ground; the catastrophe came because most Haitians are poor and vulnerable.

Why are so many Haitians so vulnerable? Asking why people are poor is different from asking why a country is poor. Some have blamed Haiti's poverty on culture or religion; others cite the country's history of slavery and colonialism; yet others decry government corruption or decades of unfocused foreign aid. There are no simple explanations. The one thing we understand is that Haiti has been destitute and will continue to be so for a long time.

We do know, however, why many individual Haitians are poor. For a large number, there is a clear reason: Many have been willing and able to leave Haiti for American shores, but armed agents of the U.S. government have forcibly stopped them or deterred them from trying. If they had not been stopped, virtually none of them would have been as poor and vulnerable as they were on Jan. 12.

In research I conducted with economists Claudio Montenegro and Lant Pritchett, we compared how much Haitians earn in the United States vs. Haiti. A moderately educated adult male, born and schooled in Haiti, typically enjoys a standard of living more than six times greater in the United States than in his homeland. In other words, U.S. policy wipes out more than 80 percent of a Haitian's earning power when it keeps him from coming to the United States. This affects everything from the food he can buy to the construction materials he can afford. The difference has nothing to do with his ability or effort; it results purely from where he is.

After the earthquake, the Obama administration quickly suspended the deportation of Haitians already residing illegally in the United States (a population estimated at 100,000 to 200,000) for 18 months. That's a wise and welcome step, but an insufficient one. The United States has deported only around 1,000 Haitians per year recently, so a brief halt will make a limited difference in who lives where. Secretary of State Hillary Clinton emphasized Thursday that the new policy will not apply to Haitians seeking to come here now. "Our ordinary and regular immigration laws will apply going forward, which means that we are not going to be accepting into the United States Haitians who are attempting to make it to our shores. They will be interdicted. They will be repatriated."

Yet Haitians willing to emigrate today would typically experience vast and immediate increases in their standard of living and security -- a goal the administration no doubt supports. That is why so many have been willing to leave Haiti, braving ocean blockades and other risks, even before the quake. Between 1982 and 2009, the U.S. Coast Guard stopped 114,716 Haitians on their way to the United States, forcing them to go back, and such unsuccessful attempts must certainly have deterred an even larger number from even trying to leave. Last March, 51 percent of Haitians polled told Gallup that, given the opportunity, they would leave their country permanently.

I am not suggesting that, if some of these people died in the earthquake, U.S. immigration policy is responsible. But it would be just as ludicrous to contend that we could not foresee very bad things happening to people forced to live in extreme poverty. Life in destitution is a brittle existence. There is no extra money to buy good building materials, invest in quality schooling or take preventive health measures. So when shocks arrive, as they must -- an earthquake, a job loss, a sickness -- problems become calamities. Such consequences are predictable. For this reason, the United States is complicit in the agony many Haitians are now suffering.

After Hurricane Katrina devastated New Orleans and the Gulf Coast in 2005, one of the principal ways its victims helped themselves was by leaving. Katrina prompted one of the biggest resettlements in American history. Who would have blocked Interstate 10 with armed guards, forcing hundreds of thousands of people to suffer in the disaster zone, no matter how much assistance was coming in from outside? We wouldn't have done that, because it would have made us collectively responsible for their continued suffering. Why then, in the thoughtful debate that has emerged over how best to aid Haiti and help its citizens help themselves, are Americans still quiet about this sinister face of our immigration policy?

Of course, a natural disaster by itself is not a sufficient reason to eliminate restrictions on the movement of Haitians. International migration has complex effects: It can shape societies, labor markets and electorates. And disasters such as Haiti's earthquake are aggravated by countless political, social and economic forces, in their locales and beyond. But even taken alone, U.S. immigration law has a huge impact on poor people all over the world. We should consider this when debating immigration reform as well as aid and development.

Currently, we allow a trickle of about 21,000 Haitian immigrants, on average, to enter the United States legally each year; most of them are able to come only because they are lucky enough to have a relative already here. What evidence do we have that we could not absorb triple that number, or even more? For years, we have been accepting close to 1 million permanent immigrants annually from around the world, with no lasting effects on the earnings of the average American worker. And while most economic studies find that such immigration may have lowered the wages of U.S. high school dropouts by a few percentage points, many of those dropouts are immigrants themselves, already earning far more than they would in their country of origin. A high school dropout in the United States earns an average of $24,000 a year -- about seven times the wages of a typical Haitian worker.

Beyond permanent immigrants, 498 Haitians entered the United States in 2008 on temporary seasonal worker visas, known as H-2 visas. Even in a time of economic crisis, the gigantic American economy could welcome many times that number of temporary Haitian workers. Guest workers help our economy grow and recover by giving employers greater flexibility in their hiring and investment decisions, particularly in hard-hit sectors such as textiles, transportation and construction.

Meanwhile, those workers would do more good for themselves and their families than any amount of aid could do for them. And people remaining in Haiti would benefit enormously. Haiti already gets close to $2 billion per year -- about a third of its income -- in cash remittances from its citizens living abroad. That's nearly 100 times as much as generous Americans have donated to Haiti via their cellphones. And unlike foreign aid, remittances go directly to families.

The earthquake in Haiti has laid bare the consequences of our restrictive immigration policies, particularly their effects on desperately poor people overseas. Countless Americans have been moved by the images and stories from Haiti, and have showed their solidarity and generosity with their wallets. A golden door visa to America, whether temporary or permanent, would have a larger and ultimately more lasting impact on the lives of the world's poorest, in Haiti and beyond.

Michael A. Clemens is a research fellow at the Center for Global Development and an affiliated associate professor of public policy at Georgetown University.