Obama has mobilized a huge emergency aid effort for Haiti and officials say the United States will remain involved in rebuilding the impoverished Caribbean nation so that, after some 200 years of independence, it can eventually stand on its own.
"I want the people of Haiti to know that we will do what it takes to save lives and to help them get back on their feet," Obama said on Friday. "The scale of the devastation is extraordinary ... and the losses are heartbreaking."
This is what could happen next.
THE U.S. EFFECTIVELY TAKES OVER
U.S. officials have stressed that the assistance effort, which involves thousands of U.S. soldiers, sailors and Marines along with civilian search-and-rescue teams, is being organized in cooperation with the Haitian government led by President Rene Preval.
But the Haitian government, fragile at the best of times, is almost entirely out of contact, meaning that many of the operational decisions must come from Washington.
Experts say the United States has few options: it must either step up to the task of relief rebuilding, or open itself to criticism and as a possible new flood of Haitian refugees.
Dan Erikson, a Haiti specialist at the Inter-American Dialogue, a Washington-based think tank, said at least in the short term the United States was calling the shots.
"Haiti had barely functioning ministries even before the earthquake," Erikson said. "The Obama administration can describe this as a partnership, but it is one where one partner is doing all the work and has all the authority."
U.S. aid chief Rajiv Shah said the strategy was to "saturate" assistance networks run by the United Nations and non-governmental organizations -- after which U.S. forces will start delivering emergency help themselves.
It will not be the first time U.S. soldiers have taken the lead in Haiti, the hemisphere's poorest country. After decades of political turbulence, the United States first sent troops to Haiti in 1915. They stayed 19 years.
More recently, former President Bill Clinton helped restore President Jean-Bertrand Aristide after he was ousted by the military in 1991. But President George W. Bush did little to help Aristide stay in office when his second term was cut short in 2004 by an armed revolt.
Aristide, speaking from exile in South Africa, has offered to return -- which could complicate things.
"What happens if the Venezuelans decide to fly him back?" said Larry Birns, director of the Council on Hemispheric Affairs. "Until there is some kind of political resolution, it is going to be very hard to have rehabilitation."
UNITED NATIONS TAKES THE LEAD
U.S. officials sketch out a long-term strategy under which the United Nations -- which already has a peacekeeping force of about 9,000 in the country -- takes the lead.
While U.S. forces will contribute much of the initial emergency earthquake response, over time this will shift to a broad-based international assistance project that will concentrate on areas such as energy, farming and healthcare.
"Before this earthquake, we weren't talking about restoring (Haiti) we were talking about building a whole new country, former President Clinton said on U.S. television on Sunday.
"And there was a government plan that they developed in cooperation with the U.N., but it was their plan. And what I believe will happen is they will take all this devastation into account, all the work that has to be done, and they will rewrite their plan."
Coordination could be simple. Bill Clinton is already the U.N. special envoy for Haiti, and repeated donor conferences have established a well-known set of development priorities as well as a mechanism -- the Interim Cooperation Framework -- for delivering the help.
U.N. and NGO offices in Haiti are themselves struggling with the quake's aftermath. But given time, analysts say they should be well positioned to help channel assistance.
THE HELP DRIES UP
Some analysts say perhaps the biggest fear is that time will push Haiti off the priority list as other disasters intervene. For Haiti, already among the world's least developed nations, this could be a compound catastrophe.
"Donor fatigue is a very real concept," Birns said.
With a population of 9 million, an annual per capita income of just $560 and high infant mortality and HIV/AIDS rates, Haiti needs help virtually across the board but often lacks the ability to handle it when it comes.
"Often a lot more money is pledged than is actually delivered. And once the money is delivered, the Haitian government doesn't have the capacity to execute so the money doesn't get spent," said Erikson.
Still, like many development experts, he saw the earthquake as a possible fresh start for Haiti in its relations with its powerful northern neighbor -- who this time is intervening for humanitarian, rather than political, reasons.
"I think we ought to care from a humanitarian perspective and I also think from a strategic perspective because it makes sense to have a stable democracy in our neighborhood," former President George Bush said in a U.S. television interview.