by Walter Isaacson, TIME

Khung Thoung Sinh, 3, is held by a nurse at Peace village inside the Tu Du hospital in Ho Chi Minh City, Vietnam on May 2, 2005. He was born without eyes having been deformed since birth from what may be the effects of defoliant Agent Orange.

Clean up after yourself. It’s a rule that we learn early in life. Now, more than 30 years after the U.S. pulled out of Vietnam, the time has come to follow that rule. In Vietnam these days, unlike many other places, both the people and their leaders are generally friendly toward the U.S. Vietnam has just joined the World Trade Organization, and America is both its largest export market and source of foreign investment. Intel is building a $1 billion chipmaking plant near Ho Chi Minh City.

That’s heartening, given that a generation ago we were bogged down in a war in Vietnam that seemed almost as intractable as the Iraq war does today. It’s also a cause for humility because it shows that dominoes don’t always fall as predicted. After the communists won in Vietnam, they got into wars with the communists in Cambodia and then China.

There is, however, one wound still festering. During the Vietnam War, America sprayed close to 20 million gal. of Agent Orange, a herbicide that defoliated forests and left behind a residue of dioxin. The U.S. military also left behind 28 hot spots where Agent Orange had been used or stored that have not been properly contained. The Vietnamese say the dioxin is responsible for such disabilities as muscular and skeletal disorders and such birth defects as mental retardation. Studies at the University of Hanoi indicate a higher incidence of these problems among people who were exposed to dioxin.

I have just returned from a trip up and down Vietnam with two colleagues from the Aspen Institute that was sponsored by the Ford Foundation, which under its president, Susan Berresford, and Vietnam director, Charles Bailey, has led the way in finding practical solutions to the Agent Orange problem. In the areas around the Da Nang airport, which is on the site of a former American air base, high levels of dioxin have been detected. We walked the barren ground around the air base and went to a house near one of the ponds, which belatedly were closed for fishing once tests showed the levels of the poison.

The responsibility for these health problems is less clear. In low-lying Quang Ngai province, south of Da Nang, where the spraying of Agent Orange was especially heavy, there are almost 15,000 residents officially classified by the Vietnamese government as dioxin victims. We also went to Thai Binh province, along the northern coast. Although it is far from the sprayed areas, a large proportion of its male population fought in the war, and there is a high incidence of birth defects in subsequent generations there.

Scientists have not been able to prove a direct link between Agent Orange and the disabilities, and attempts by American and Vietnamese officials to come to a consensus have not succeeded. Indeed, efforts to resolve the issue will remain paralyzed if both sides insist on waiting for scientific proof.

A practical and sensible resolution is possible. The U.S. should help immediately to contain and then clean up the contaminated sites. After all, we made the mess. Michael Marine, the departing U.S. ambassador in Hanoi, has been able to win a small amount of funding from Washington, supplemented by the Ford Foundation, to start this process.

As for the health concerns, there is no need to pin precise blame or liability. They can be addressed as a humanitarian issue rather than as a compensation case. From Thai Binh down to Quang Ngai province, there is a need for rehabilitation centers, health clinics, family counseling, and education for the afflicted children who cannot go to regular schools. Out of both a sense of duty and a spirit of decency, U.S. government aid programs and private philanthropies should step forward to settle this last remaining dispute from the Vietnam War.

Over the past few months, there has been increased public awareness of the issue in the U.S., including a brutally vivid article by Christopher Hitchens and photographer James Nachtwey in last August’s Vanity Fair. When President Bush visited Vietnam in November, the joint statement he issued with Vietnamese President Nguyen Minh Triet cautiously referred to the need “to address the environmental contamination near former dioxin storage sites” and for “humanitarian assistance … to Vietnamese with disabilities.” Should Congress and the Defense Department choose to get with this program, they could go a long way toward resolving this crucial issue by the time President Triet visits Washington in June.

Only then will America finally have closed the last chapter of the Vietnam War and turned its former adversary into a solid strategic ally. And addressing this issue will remind us that living up to our values and showing basic decency is, in fact, the best way to win hearts and minds.