Presidents of Chile Michelle Bachelet, Argentina Cristina Fernandez, the US Barack Obama and Brazil Inacio Lula da Silva (L-R) talk before the opening ceremony of the 5th Summit of the Americas in Port of Spain April 17, 2009. [Agencies]

"But I pledge to you that we seek an equal partnership," Obama said. "There is no senior partner and junior partner in our relations."

Such an idea -- that the United States is equal, despite being keeper of the world's most powerful military and leader of an economy that helps steer the globe -- was telling.

Obama's drive to reshape the image of the United States as a humble, cooperative partner is perhaps his most significant mission here in this Caribbean nation. Grappling with an economic swoon that has touched them all, the heads of 34 nations have gathered for the first time in almost four years to fashion a fresh agenda -- and in some cases, to size up Obama.

"I'm here to launch a new chapter of engagement that will be sustained throughout my administration," Obama said at the opening of the Summit of the Americas in the two-island nation of Trinidad and Tobago. He had entered the room to a roar of applause and was singled out for attention by all the other speakers.