The rest of the world and even quite a few Americans are uncomfortable with the globe-trotting U.S. military. But in future years they will see much more of it.

The causes will be more related to the natural environment than to terrorism. Just ask the earthquake victims in northern Pakistan, where eight American military helicopters have now arrived with relief supplies — the start of an aid effort by the military's Central Command that will include airborne reconnaissance and heavy-lifting equipment.

With the global population now at six billion, humans are living in urban concentrations in an unprecedented number of seismically, climatically and environmentally fragile areas. The earthquake-stricken region of Pakistan saw a doubling of its population in recent decades, certainly a factor in the death toll of more than 20,000.

The Indian Ocean tsunami last December showed the risks to rapidly growing cities from Africa to Southeast Asia. China's booming population occupies flood zones.

When such disasters occur, security systems break down and lawlessness erupts. The first effect of the earthquake in the Pakistan town of Muzaffarabad was widespread looting — just as in New Orleans. Relief aid is undermined unless those who would help the victims can monopolize the use of force. That requires troops.

But even using our troops in our own country is controversial: the Posse Comitatus Act of 1878 strictly limits the use of troops inside the United States. The Gulf Coast devastation has helped remind us that this law was enacted in a rural America at a time when natural disasters took a relatively small human toll, and such calamities were viewed more fatalistically.

In a nation and a world where mass media and the Internet spread the word of disaster so effectively, impassioned calls to do something can quickly erode constitutional concerns, political differences and worries over sovereignty.

Just as Pakistan has now agreed to accept aid from its rival India, Iran accepted help from the United States Air Force after the earthquake in Bam in 2003. The very people who typically denounce the American military will surely be complaining about its absence should our troops not show up after a major natural calamity.

Indeed, because of our military's ability to move quickly into new territory and establish security perimeters, it is emerging as the world's most effective emergency relief organization.

The distinctions between war and relief, between domestic and foreign deployments, are breaking down. This is especially true within the Special Operations contingents. As democratization takes hold, and as feisty local news outlets arise in previously autocratic Third World countries, the military's Special Operations Command can no longer carry out commando-style raids at will.

In recent years, I have been a witness to a shift in emphasis from "direct action" to the soft side of "unconventional war": undertaking relief work in places like the southern Philippines and northern Kenya to win good will and, informally, to pick up intelligence on America's terrorist enemies.

On a larger scale, the disaster relief provided by the aircraft carrier Abraham Lincoln after the Indian Ocean tsunami probably did more to improve America's image in Asia in relation to that of China than any conventional training deployment.

So how can the Pentagon become better at emergency relief without impeding its ability to fight wars? First, it must continue to train primarily for combat. Combat provides a vital esprit de corps, and the skills that are honed in preparation for combat are also the most valuable tools for disaster relief.

In addition, just as our Special Operations division has special units for select commando operations (like the Army Special Forces who can deploy in the snow on skis from helicopters), it should likewise develop more niche capacities for missions such as rescuing people from rubble and flood waters.

Also, the Central Command and each of the military's other geographic-area commands need to create permanent planning units to anticipate disaster responses in their spheres of responsibility. The diplomatic gains we make when our military arrives on scene can be vastly increased if those troops arrive quickly as part of an advance plan.

Finally, just as civilian nongovernmental groups are often needlessly antagonistic toward the American military, our troops are sometimes guilty of having a gruff attitude toward the civilian workers. If American soldiers want to be more effective and better liked abroad, they'll have to be able to work in a coordinated way with, or even alongside, nongovernmental groups like Doctors Without Borders and the International Red Cross.

The Pentagon is a big fan of peacetime "combined ops" with foreign militaries, and this term should be expanded to include training with civilian do-gooder groups as well. (To its credit, the Navy has plans to experiment with this by embedding personnel from nongovernmental organizations on its hospital ships.)

Will a new emphasis on disaster relief further strain an already overstretched military? No. Most of our deployments around the world, for either military or humanitarian efforts, involve small groups, perhaps several platoons. It is Iraq that's been breaking the system, and as we gradually lower our troop levels in that country, there will be more capacity for operations that provide significant diplomatic benefits.

Fluidity and flexibility now define military affairs. There is no better example than Pakistan, a country always on the brink of dissolving into chaos, which would result in our having to place Special Operations forces in great numbers inside the tribal groups and agencies along the Afghan border. In any case, hunting down al-Qaida in its lair will be impossible without the good will of the local population.

That attitude can be generated by relief work of the kind taking place in Kashmir. It's the classic counterinsurgency model: winning without firing a shot. And it's what the future of the American military increasingly will be about.

Robert D. Kaplan is a correspondent for the Atlantic Monthly and author of "Imperial Grunts: The American Military on the Ground."