It was a war the president did not want to fight. In the end, he had no choice. He ordered 40,000 additional troops into the fray.

Upon his 2006 swearing-in as president of Mexico, Felipe Calderon inherited a nation at war with itself. It's a multifront conflict, with a handful of powerful cartels fighting to control a network of multinational criminal enterprises.

Make no mistake; it is nothing less than a war. One cartel, Los Zetas, was even founded by pros: former commandos and deserters from the Mexican military.

The group employs paramilitary tactics with deadly efficiency. In July, eight Zetas armed with assault rifles and 40-milimeter grenade launchers blasted the home of the Veracruz police chief, slaughtering him, his wife and their children.

The Drug Enforcement Agency's Ralph Reyes told CNN, "The Zetas have obviously assumed the role of being the No. 1 organization responsible for the majority of the homicides, the narcotic-related homicides, the beheadings, the kidnappings, the extortions that take place in Mexico."

President Calderon has used the military to fight Los Zetas and the other cartels. At the same time, he is trying to reform and reorganize the police and judiciary -- vital institutions that have been cowed, infiltrated or corrupted by the cartels.

The war continues. More than 5,000 homicides are attributed to Mexico's crime war so far this year. With a month to go, the killing could well match last year's butcher's bill of more than 7,000.

This war is not just Mexico's problem. The cartels reach throughout the hemisphere, from Latin America to Canada. They represent a direct threat to America. George W. Bush's departing CIA chief, Michael Hayden, declared that the cartels could well rank among the top security challenges faced by the incoming administration.

In the first six months of President Obama's tenure, Mexico got a good deal of attention from the White House and the mainstream press. But interest in the issue seems to be flagging, even though the violence has not.

The new White House started out strong, endorsing the Merida Initiative. Passed by Congress in 2008, Merida provides almost a half-billion dollars in aid to fight the cartels.

The initiative was a real breakthrough. For the first time, a Mexican government demonstrated willingness to partner with America on a major security effort.

But U.S. policy can't stand pat. President Obama now needs to find a way to keep the momentum going.

As a next step, the United States should do all it can to convince Mexico to join NORAD, the North American Aerospace Defense Command. NORAD is a binational organization, run jointly by the U.S. and Canada.

Established during the Cold War to provide early warning of any approaching Soviet bombers, today the command helps defend against both terrorist and criminal threats by monitoring North American airspace and providing situational awareness of what's happening on the seas.

U.S.-Mexican relations are complex. There is a lot of bad history between the two nations. But there are also many good reasons for Mexico to join NORAD.

First, it represents no threat to Mexican sovereignty or security. Just ask the Canadians. They have partnered with the U.S. for 50 years and never had a problem.

Second, Mexico needs NORAD. The command could offer vital assistance in organizing and sharing information to target traffickers operating at air and sea.

Third, NORAD could provide a coordinated military structure that would let Mexico better cooperate with the U.S. and Canada on a host common security issues.

Adding Mexico to NORAD makes sense for the U.S. as well. Though some elements of the Mexican military have been infiltrated by the cartels, U.S. intelligence has excellent protocols for vetting all individuals who might participate in the command. That would limit the potential for security lapses. Likewise, the organization of NORAD ensures that U.S. forces will never be under the control of foreign nation.

Mexico cannot win its war without America's help. America can't afford for Mexico to lose. It is time for both nations to make the next move in building effective civil-military cooperation. Joining NORAD is the right step.

James Jay Carafano, Ph.D., is Assistant Director of the Kathryn and Shelby Cullom Davis Institute for International Studies and Senior Research Fellow for National Security and Homeland Security in the Douglas and Sarah Allison Center for Foreign Policy Studies at The Heritage Foundation.