The tragedy unfolding in Haiti has elicited an outpouring of sympathy, and it is hardly surprising that governments and NGOs from all over the globe are mobilizing resources to aid in recovery. Help is flowing to the shattered island: teams trained in rescue operations, emergency medical services, security personnel, and financial aid. This type of assistance will likely continue for some time.

The U.S. military is also involved. Several Navy and Coast Guard vessels shipped out almost immediately. A few thousand Marines are helping to restore order, and more might soon be on the way. Such a ground presence makes sense, provided that the mission is carefully defined, and the long-term expectations are tempered by a dose of humility. The United States has, after all, intervened repeatedly in Haiti, and it remains the poorest country in the hemisphere. One might even conclude that our interventions have contributed to Haiti’s chronic problems, a consideration which should give pause to those calling for the United States to commit to a long-term project to fix the country.

One can make an argument against sending military assets to deal with such crises. A nation’s military is designed and built for one purpose — to defend the nation — and when it is deployed for missions that do not serve that narrow purpose there is a risk that the institutions will be rendered less capable of responding to genuine threats. I question the wisdom of humanitarian intervention on those grounds in my book, The Power Problem, stipulating, among other things, that the U.S. military should be sent abroad only when vital U.S. interests are at stake.

All that said, President Obama’s decision to swiftly deploy U.S. personnel to Haiti is appropriate on at least two grounds. First, sending troops into harm’s way — and usually into the middle of a civil conflict, as we did in the Balkans and in Iraq — is very different from mobilizing our formidable military assets to ameliorate suffering after a natural disaster. The latter types of interventions are less likely to engender the ire of the people on the losing end (and there always are losers). Humanitarian missions are also less likely to arouse the suspicion of neighbors who might question the intervener’s intentions. Indeed, there was a measurable outpouring of support and goodwill toward the United States after the Bush administration deployed U.S. military personnel in and around Indonesia following the horrific tsunami of late 2004. Genuine humanitarian missions, “armed philanthropy” as MIT’s Barry Posen calls it, are likely to be far less costly than armed regime change/nation-building missions that must contend with insurgents intent on taking their country back from the foreign occupier.

Another important consideration is a country’s interests in its respective region. Humanitarian crises, even those whose effects are confined within a particular country’s borders, often pose a national security threat to neighboring states. What has happened in Haiti over the past 48 hours might meet that criteria, but the White House’s immediate motivations seem purely altruistic. My frustration is that the U.S. policy since the end of the Cold War of actively discouraging other countries from defending themselves ensures that they will have little to offer when a similar natural disaster occurs in their own backyard, which means that the U.S. military is expected to act — even when our own interests are not at stake.

But that is a discussion for another time. The scale of the tragedy in nearby Haiti cries out for swift action, and I am pleased to see that many organizations — both public and private — have stepped forward to help. I wish these efforts well.