President Bush reopened the old debate on the Vietnam War recently by saying in his visit to Hanoi that the lesson he drew from that bitter experience was that, in Iraq, “We’ll succeed unless we quit.”

That aligned the president with the small group of bitter-enders who still insist that the United States could have won in Vietnam if President Lyndon Johnson had let the generals run the war, if Congress hadn’t cut back funding and if the media had emphasized the positives instead of the negatives.

The outcome of Vietnam may have been doomed from the start. The American intervention began when President Harry S. Truman started bankrolling the French effort after World War II to resume its colonialist rule of Indochina. President Dwight D. Eisenhower continued that obligation even after the Communist forces defeated the French army in the siege of the North Vietnamese village of Dien Bien Phu. President Kennedy made it an American cause, sent in 16,000 “military advisers” and started American combat involvement. President Johnson escalated U.S. deployments to more than 500,000 troops. President Nixon slowly “Vietnamized” the war, withdrawing most U.S. troops but financing South Vietnam’s forces and stepping up the bombing of North Vietnam. That meant an additional 10,000 U.S. war dead. The end came in 1975 under President Ford.

If staying the course is not the true lesson, there are others that could apply to the Iraq war:

Don’t start a “war of choice” without an adequate force, a reasonable goal, an honest disclosure of the pros and cons and the support of an informed public.

Have a practical reason for U.S. involvement. The presidents who waged the Vietnam War mistook a nationalistic insurgency for a tentacle of international Communism. The Bush war planners persuaded themselves that an invasion of Iraq would be greeted by cheering throngs and would lead to a democratic model for a peaceful Middle East.

Be skeptical of rosy reports of military and political progress and promises of “light at the end of the tunnel.”

The Iraq war, after more than three years, shows signs of entering its final phase. The Baker-Hamilton Iraq Study Group’s report, due next month, may point the way toward a resolution. With it may come a final lesson: Losing doesn’t always lead to a bad result. Vietnam, for all its Communist leadership and human rights abuses, has improved as it has developed a vibrant market economy and is already a peaceful economic partner.