Could this weekend's gathering of 33 Western Hemisphere leaders be the last Summit of the Americas?
The question remained unanswered ahead of Sunday's private retreat of the leaders.
Washington was standing fast against including Cuba in future summits and there was squabbling over this meeting's final declaration.
"All the countries here in Latin American and the Caribbean want Cuba to be present. But the United States won't accept," President Evo Morales of Bolivia told reporters Saturday. "It's like a dictatorship."
Morales expelled the U.S. ambassador in 2008 for allegedly inciting his opponents and talks on restoring ambassadors are currently stalled.
Bolivia is among leftist nations that have been insistent that this weekend's gathering in this Caribbean colonial port, which wraps up at midday Sunday, will be the last regional summit under Organization of American States auspices unless Cuba is invited in the future.
President Barack Obama's peers lectured him Saturday over his unflagging opposition to Cuban participation due to U.S. objections to the communist-governed Caribbean island's lack of democracy.
He was also criticized for refusing to abandon a drug war that has claimed tens of thousands of lives and undermined governments, although he didn't shy from listening to arguments on the other side.
"I don't mind a debate around issues like decriminalization," he said in a pre-summit interview with Univision television. "I personally don't agree that that's a solution to the problem."
"But I think that given the pressures that a lot of governments face here _ underesourced, overwhelmed by violence _ it's completly understandable that they would look for new approaches," Obama added.
The summit's host, President Juan Manuel Santos of Colombia, urged a reconsideration of the war on narcotics, citing the irony of Colombia's successes: While it extradites hundreds of alleged drug traffickers for trial to the U.S., criminals turn to other countries where law enforcement is weaker. Central America and Mexico, in particular, are bleeding as traffickers shift to countries of lesser resistance.
"We know that our success has (negatively) affected other countries and we are pedaling and pedaling and pedaling like we're on a stationary bike," said Santos. "The moment has come to analyze if what we're doing is best or if we can find a more effective and cheaper alternative for society."
For some, the summit was overshadowed by an embarrassing scandal involving prostitutes and U.S. Secret Service agents that widened when the U.S. military said five service members staying at the same hotel might have also been involved in misconduct.
U.S. Rep. Peter King told The Associated Press after being briefed on the investigation that "close to" all 11 of the Secret Service agents who were put on leave Saturday had taken women to their rooms at a hotel a few blocks from where Obama is staying. He said the women were "presumed to be prostitutes" but investigators were interviewing the agents.
Three waiters at the hotel told the AP that about a dozen U.S. government workers they presumed were the Secret Service agents had spent a week drinking heavily. One said he witnessed their apparent supervisor line them up and scold them on the hotel's back terrace at about 4 p.m. Thursday.
Immediately thereafter, the men packed their bags and left, said the waiter, who spoke on condition of anonymity because, like his colleagues, he feared for his job.
The summit's final declaration was uncertain going into Sunday because the foreign ministers of Venezuela, Argentina and Uruguay said their presidents wouldn't sign it unless the U.S. and Canada removed their veto of future Cuban participation.
The charismatic Obama might be able to charm the region's leaders as he did in 2009 with a pledge of being an "equal partner," but he would also have to prove the U.S. was committed to engage them more consistently.
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. It has surpassed the U.S. in trade with Brazil, Chile and Peru and is a close second in Argentina and Colombia.
The Cuba issue led Ecuadorean President Rafael Correa to boycott the summit, while moderates such as Santos and President Dilma Rousseff of Brazil said there should be no more America's summits without the communist island.
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.
Associated Press writer Marco Sibaja contributed to this report