Washington ? New tactics favored by U.S. military officers in Iraq borrow heavily from the end of another war that might seem an unlikely source for a winning strategy: Vietnam.

The tactics – an influx of military advisers and a speeded-up handover to indigenous forces followed by a gradual U.S. withdrawal – resemble those in place as the U.S. effort in Vietnam reached its end.

In historical assessments and the American recollection, Vietnam was the unwinnable war. But to many in the armed forces, Vietnam as a war actually was on its way to succeeding when the Nixon administration and Congress, bowing to public impatience, pulled the plug: first withdrawing U.S. combat forces and then blocking funding and supplies to the South Vietnamese army.

If they hadn’t, the South Vietnamese army, which had been bolstered by U.S. advisers and a more focused “hearts-and-minds” campaign in the later stages of the war, could have fended off the communist North, military thinkers have argued.

In their view, progress was undermined by President Nixon’s decision to begin withdrawing U.S. troops in 1969 in the face of political pressure at home, despite military objections that the South Vietnamese army was not ready to go it alone. Another key U.S. mistake, they contend, were the deep cuts by Congress to military aid to Saigon beginning in 1974.

For many in the military, the lesson of Vietnam is clear: Maintain public support and be patient.

Consciously or not, President Bush encapsulated that view during his recent trip to Hanoi, where he was asked whether there were lessons in Vietnam for the war in Iraq. Instead of military tactics or strategy, he answered by talking about the impatience of the American public, and how success in war can be slow.

“We’ll succeed unless we quit,” Bush said.

President Bush is accompanied by first lady Laura Bush and Chairman of the Ho Chi Minh City People's Committee Le Hoang Quang earlier this week During a visit to Ho Chi Minh City, Vietnam. Bush's trip to Vietnam brought up historical parallels between the war there and the current war in Iraq.

Far from universal

The view that Vietnam could have been won if public opinion and political will had continued to support the war effort is far from universal, particularly among historians outside the military.

Stanley Karnow, a Pulitzer Prize-winning journalist who covered the war from the day the first American was killed in 1959 to its ultimate end, said Hanoi was nowhere near capitulation by 1973 when the Paris Peace Accords were signed.

“They’re clutching at some sort of way to justify hanging on in Iraq,” said Karnow, whose “Vietnam: A History” frequently is considered the definitive account of the conflict.

“The war in Vietnam, in my estimation, was unwinnable for the simple, basic reason that we were up against an enemy that was prepared to take on unlimited losses. They would have gone on fighting endlessly.”

For years, the debate about the end of the Vietnam War occupied students and scholars in the military’s academies and war colleges. But with the Pentagon struggling to find answers in Iraq, the lessons of Vietnam have taken on more than an academic interest.

The course that senior military officers now appear to be steering in Iraq mirrors the “Vietnamization” program implemented by Nixon and his military chief in Vietnam, Army Gen. Creighton Abrams, in the late stages of the war.

Army Gen. John P. Abizaid, leader of all U.S. forces in the Middle East, laid out that path at congressional hearings last week. He said the biggest change he anticipates in the coming months is a large-scale increase in U.S. advisers.

He also said he hopes to hand over responsibility for security to Iraqi forces in less than a year – faster than Army Gen. George Casey Jr., the U.S. top officer in Iraq, had estimated just weeks earlier – and spelled out his resistance to an increase in American combat troops.

“I believe that more American forces prevent the Iraqis from doing more,” Abizaid told the Senate Armed Services Committee. “If more troops need to come in, they need to come in to make the Iraqi army stronger.”

Familiar strategy

Among the administration’s Iraq war planners, the influence of the late Abrams has been felt before.

The strategy of “clear, hold and build,” in which U.S. forces remain in captured towns to provide security while reconstruction begins, first was articulated by Secretary of State Condoleezza Rice more than a year ago and closely echoes Abrams’ “clear and hold” strategy in Vietnam.