President Obama arrived in Mexico Sunday to meet with his Mexican and Canadian counterparts at the North American Leaders Summit, where he will be confronted with the weight of a myriad of lingering, unresolved issues from the scourge of drug cartels to the ripple effects of the faltering US economy.

The annual trilateral gathering began in 2005 under President George W. Bush. However, Mr. Obama’s inaugural summit appearance, held this year in the Western city of Guadalajara, will tackle more urgent and widespread issues.

One of the most pressing of which is the Mexican drug cartel crisis. Drug-related violence in Mexico is coming to a crescendo; with the July being deadliest month since Mexican President Felipe Calderon began a fierce crackdown on the out-of-control cartels. Eight hundred and fifty people died last month in the swirl of violence and illicit drug-running that is taking root in Mexican society. And that is the crux of the issue facing a delay in assistance the US has promised to provide the Mexicans in their battle.

Under the Merida Initiative, begun under Mr. Bush in 2007, Mexico is supposed to receive $1.4 billion dollars-worth of anti-drug equipment and training over a three-year period. More than $100 million of that has been delayed due to concerns over human rights abuses by the Mexican Army and police in their assault on traffickers.

“The law withholds 15 percent of the Merida funds until the Secretary of State reports to Congress that the Mexican government is meeting four reåquirements, including prosecuting military and police officers who violate human rights,” Vermont Senator Patrick Leahy, the Democrat who chairs a subcommittee that oversees foreign aid spending said in a statement. “Those requirements have not been met, so it is premature [for the State Department] to send the report to congress,” he said.

But with mounting deaths, some extremely violent, Calderon is likely to appeal directly to Mr. Obama for the aid to be dispensed more quickly when the two meet Sunday.

The administration is loathe to outwardly criticize Calderon’s handling of the military efforts, “I think President Calderon has to be complimented for the aggressive role and posture that he has taken vis-à-vis the drug cartels. That role and the activities of the Mexican military is a Mexican government decision,” Deputy National Security Advisor John Brennan told reporters Thursday.

The two-day summit, which will include Canadian Prime Minister Stephen Harper, will also touch on the global economic crisis, which was spawned in the US. Mexico and Canada, who rely on the US’s buying power for 80% of their exports, are feeling the impact of that recession.

Compounding troubles for both the US and Mexico, is the countries’ trucking dispute. Congressional concerns over the safety of Mexican trucks on US roads prompted a ban on those trucks in the US; a violation of the North American Free Trade Agreement (NAFTA). In turn, Mexico retaliated with 10-20% tariffs on 89 US products entering Mexico. Both sides have vested economic interests in getting the problem solved.

This is not to say the Canadians don’t have their own concerns. Hot topic number one is the “Buy American” provision in the stimulus bill, which Canada was supposed to be exempted from.

Also not to be forgotten are preparations for the H1N1 flu virus. The three leaders are trying to get ahead of the curve, before the virus picks up steam, “I think everybody recognizes that H1N1 is going to be a challenge for all of us and there are people who are going to be getting sick in the fall and die. People have been dying over the past number of months from H1N1. The strategy and the effort on the part of the governments is to make sure we do everything possible and we collaborate to minimize the impact and make sure that the severity of the illness is kept at a minimum,” Brennan noted.

The summit isn’t expected to produce any tangible results. It’s seen as just another piece of the on-going dialogue.