On his maiden voyage outside the United States as president, Barack Obama sought to reassure free-trading Canadians that his country is not cultivating a protectionist streak as its economy falls apart and hemorrhages jobs.

Canadian Prime Minister Stephen Harper (second left) watches U.S. President Barack Obama (second right) prepare to sign the guest book at Parliament Hill in Ottawa on Feb. 19. AP PHOTO

"I want to grow trade and not contract it," Obama declared Feb. 19 during a quick visit to head off a chill in relations with its northern neighbor.

The president stuck to his pledge eventually to seek changes in the 1994 North American Free Trade Agreement to increase enforcement of labor and environmental standards. He said, however, that he intends to do so in a way "that is not disruptive to the extraordinarily important trade relationships that exist between the United States and Canada."

His host, Canadian Prime Minister Stephen Harper, said he might be willing to negotiate but not by "opening the whole NAFTA and unraveling what is a very complex agreement." Canada is the United States' largest trading partner and with $1.5 billion in trade between the two nations, they have the largest trading relationship in the world.

Harper sounded a similar warning on a "Buy American" clause that Congress added to the $787 billion economic stimulus package that Obama signed Feb. 17.

"We expect the United States to adhere to its international obligations," Harper said. "I can't emphasize how important it is that we do that."

Harper, who made a return visit to Obama in Washington on Feb. 24, added: "We have a partner on the North American continent that will provide leadership to the world on the climate change issue and I think that's an important development."