WHEN Americans talk about "the lessons of Vietnam," they usually mean failed policies and programs that shouldn't be repeated. But there were some successes in the Vietnam War, including an initiative to win the allegiance of captured and defecting Vietcong and North Vietnamese fighters by treating them generously and reshaping their attitudes. This idea - that harsh treatment of prisoners can be less effective than showing compassion - now deserves a test in Iraq.

The program in Vietnam was called Chieu Hoi, roughly translated as "open arms." While rarely effective against the most hard-core and high-ranking insurgents, Chieu Hoi succeeded in winning the support of nearly 200,000 fighters for the American-backed government of South Vietnam.

Under Chieu Hoi, defectors and prisoners who proved cooperative received clemency against treason charges as well as good food, health care, vocational training and jobs. At the same time, they were systematically indoctrinated with literature, classes and activities to persuade them to support the South Vietnamese government.

Studies carried out during the war by the RAND Corporation found that thousands of those former enemies who participated in Chieu Hoi became good sources of intelligence on the Communist forces, provided American advisers and troops with cultural and linguistic knowledge, enlisted civilians to support the American cause, and even took up arms against their former Vietcong and North Vietnamese comrades.