As fears of a wider swine flu outbreak grow in the international community, the leaders put the disease at the top of their roster.
Today, the three leaders pledged to enhance cooperation in combating the spread of the H1N1 influenza virus this fall.
"In anticipation of a possible fall wave of flu due to the 2009 H1N1 virus, we will look to enhance our exchange of information, ensure common understanding on the effectiveness of public health measures and share expertise," the three leaders said in a statement issued at the end of the summit.
White House homeland security czar John Brennan has warned that it is crucial to collaborate with Mexico and Canada on vaccine development and distribution, and ways to communicate with populations on how to best prevent the spread of the illness.
Obama, standing next to Calderon and Harper, on Monday vowed to continue the fight on cross-border drug cartels, a sentiment echoed by all three leaders.
Drug-related deaths in Mexico have risen since Calderon became president in December 2006, and passed 12,000 this month.
Despite some human rights groups' criticisms of the behavior of the Mexican army, Obama has stood firmly with Calderon as the cartels have increasingly branched out into the United States.
Today, he said he has confidence that under Calderon "human rights will be observed," but he did not answer the question of whether the State Department would certify that Mexico is protecting human rights.
Calderon said repeatedly that his government "has an absolute and categorical commitment with human rights."
While Obama today pledged increased cooperation on cross-border trade with both Canada and Mexico, the issue of tariffs remains a serious point of contention.
In the 1994 NAFTA agreement, the United States agreed to allow Mexican trucks to haul their loads directly into the country to expedite delivery -- as long as U.S. safety standards were met.
Two years ago, the trucks began rolling across the border, and were given a good safety rating by the Department of Transportation.
However, members of Congress and the Teamsters Union complained the trucks were unsafe. So in spring, Congress inserted a provision in the budget bill to kill the trucking program.
In retaliation, Mexico slapped on tariffs reaching $2.4 billion, which are devastating businesses that sell products to Mexico. The tariffs range from 10 percent to 45 percent and affect dozens of U.S.-made products, including grapes, Christmas trees and paper products.
Paper maker Appleton Inc., of Wisconsin, laid off 10 percent of its 2,500 employees last year and slashed benefits just to keep operating.
"I guess I would say we were treading water, given the recession," said Kent Willitts, Appleton's vice president of marketing and strategy. "This is like someone handing you a brick and saying, 'Here, keep treading water.'
"We don't even participate in the trucking program and yet, one day we wake up and our products are penalized 10 percent," he said.
It has the remaining employees worried, too.
"The layoffs came very, very close to me," said Bill Saler, a steelworker for Appleton. "If we lose any more business, I will be the next to go."
Half a country away, California grape grower John Zaninovich said he feared he might lose more than $1 million this year.
"Already, we would have shipped probably in the neighborhood of 25,000 boxes down there [to Mexico]," Zaninovich said. "To this date, we have shipped zero."
When Obama was a senator, he voted against the Mexican trucking program. But now, as president, his position seems to have shifted, and Obama talked increasingly about doing away with protectionist policies in his remarks Monday.
Obama may have to figure out a way to uphold the U.S. obligation to NAFTA agreement while also upholding his earlier safety concerns. But his administration has not yet said how it intends to do that.