Vigorous discussion among the 33 leaders is expected on drug legalization, which the Obama administration opposes. And Obama can expect to be in the minority in his opposition to Argentina's claim to the British-controlled Falkland Islands.
While Obama remains popular
Foreign ministers were wrangling behind closed doors Friday over the insistence by leftist countries that the summit's final declaration states unequivocally there be no more such gatherings without Cuba.
On top of that, key issues Latin American leaders are seeking answers for, such as Cuba, drug trafficking and immigration, may prove to be contentious during a U.S. election year. Although the charismatic Obama may be able to charm the region's leaders, he will have to convince them that the United States remains relevant to them and their countries.
"I think that the United States has to turn around and really look at Latin America with greater responsibility," Guatemalan President Otto Perez Molina told The Associated Press in Cartagena Friday. "In reality, I feel that the agenda of the United States and the agenda of Latin America countries, instead of moving in parallel to each other, or converging, are taking paths that separate them, that distance them."
In large part, declining U.S. influence comes down to waning economic clout, as China gains on the U.S. as a top trading partner throughout the region. In fact, Latin America weathered the recent
"Most countries of the region view the United States as less and less relevant to their needs—and with declining capacity to propose and carry out strategies to deal with the issues that most concern them," the Washington-based think tank the Inter-American Dialogue noted in a pre-summit report.
Colombian President Jose Manuel Santos, the summit host, said in a newspaper interview before the gathering that he's told U.S. officials that it's foolish not to better engage Latin America.
"What I've said and I've said it in the United States to a lot of people in government is, 'You'd better look to the south,' because their long-term strategic interests are in Latin America, not in distant lands," Santos said.
Obama can expect a lot of criticism over Cuba's exclusion, at U.S. insistence, from the summits since the first one in 1994.
Leaders including Santos have said they will permit no more future Summits of the Americas without the communist country's participation. Obama's administration has greatly eased family travel and remittances to Cuba, but has not dropped the half-century U.S. embargo against the island, nor moved to let it back into the Organization of American States, under whose auspices the summit is organized.
Ecuadorean President Rafael Correa was boycotting the summit over Cuba's exclusion, making him the only president in the region to do so.
Another major issue will be drug legalization, which the Obama administration firmly opposes. Santos left the idea off the official agenda but has said all possible scenarios should be explored and the U.N. should consider them.
Meeting with Argentine President Cristina Fernandez at his request, Obama can expect to discuss that country's claim to the Falkland Islands after Argentina lost a war with Britain 30 years ago while trying to seize them.
Among the hemisphere's leaders, there is nearly unanimous support for Argentina's position.
The U.S. and Canadian stances on the islands drew criticism Thursday from Venezuelan Foreign Minister Nicolas Maduro.
He told reporters the two countries "maintain their anti-historic retrograde positions of not accompanying Argentina in its fight for the Malvinas (Falklands) and by rejecting Cuba's presence in these meetings."
Obama has said he hopes to turn around the U.S. decline in the region.
Before departing on his fifth visit to the region as president, Obama told Colombia-based Caracol Radio Friday morning that he wants to expand the "powerful trading base" the United States has with Latin America, which has some of the world's fastest-growing economies.
The American leader blamed Republicans in an "obstructionist" U.S. Congress for blocking immigration reform, to which he said he's committed.
U.S. Secretary of State Hillary Clinton noted on Thursday before leaving for Cartagena that the region's countries buy more than 40 percent of U.S. exports, three times as much as China buys from the United States in net value. The region also provides more than half of the United States' imported energy.
Nonetheless, the U.N. Economic Commission for Latin America and the Caribbean says a much greater share of U.S. exports, 61 percent, went to the region a decade ago. China has surpassed the United States in trade with Brazil, Chile, and Peru and is a close second in Argentina and Colombia.
U.S. assistance to the region has also decreased, with U.S. military, police and economic aid to Latin America falling from $3.2 billion in 2009 to a proposed $2.4 billion for fiscal 2013, according to a tally by three liberal think tanks including the Washington Office on Latin America.
The U.S. isn't the only summit participant facing challenges.
The Organization of American States, composed of all the countries in the Western Hemisphere except for Cuba, organizes the summit but has lost much of its former clout with the end of the Cold War.
The OAS, to which the U.S. still pays 59 percent of its $81 million annual budget, now faces competition from a hodgepodge of new regional groupings that have emerged this century, all of them omitting the United States and Canada. They include ALBA, a bloc proposed by Venezuelan President Hugo Chavez and including Cuba; the Brazil-inspired UNASUR, encompassing South America; and CELAC, comprising 33 countries including Cuba.
Nonetheless, the OAS still plays a prominent role in the region by coordinating institutions such as the Inter-American Commission on Human Rights, an important buffer against abuses that has recently come under attack from nations including Brazil, Peru and Ecuador.
Chavez, for his part, grabbed the spotlight at past summits but has not announced if he will attend this one. Chavez has been undergoing treatment for an unspecified type of cancer in recent months, traveling frequently to Cuba for treatment.
While other leaders were traveling to Cartagena Friday afternoon, Chavez was preparing to speak to his supporters from the balcony of the presidential palace in Caracas, marking the 10th anniversary of his return to power after a failed 2002 coup.
Associated Press writers Vivian Sequera, Pedro Mendoza and Julie Pace in Cartagena, Luis Alonso in Washington and Marco Sibaja in Brasilia, Brazil, contributed to this report.
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Vivian Sequera on Twitter: http://twitter.com/vsequera