8 / 21

President Barack Obama is greeted at the airport as he arrives to Cartagena, Colombia, Friday April 13, 2012. Obama is in Cartagena to attend the sixth Summit of the Americas. (AP Photo/Carolyn Kaster)

President Barack Obama is greeted at the airport as he arrives to Cartagena, Colombia, Friday April 13, 2012. Obama is in Cartagena to attend the sixth Summit of the Americas. (AP Photo/Carolyn Kaster)

Americas Summit

Unprecedented Latin American opposition to U.S. sanctions on Cuba left President Barack Obama isolated at a summit on Sunday, April 15, and illustrated Washington's declining influence in a region being aggressively courted by China.