WASHINGTON -- Around midnight on Jan. 30, 1968, Vietcong and North Vietnamese Army troops began a massive surprise attack on U.S., South Vietnamese and allied forces across South Vietnam.

The Tet Offensive, as it came to be known, was actually a three-phase campaign, lasting from Jan. 30 - March 28, May 5 - June 15 and Aug. 17 - Sept. 23.

"The event really defined the course of the rest of the [Vietnam] war and how it ended, which was a pretty inglorious ending," said former Secretary of Defense Chuck Hagel.

Hagel, who was with the 47th Infantry Regiment in Vietnam during Tet, spoke at the "Vietnam: The Tet Offensive" panel discussion, Jan. 25, at the National Archives.

Then a 21-year-old private first class, Hagel, just two months in country, said his mechanized infantry unit sustained heavy casualties in the vicinity of Long Binh.

The attack was a complete surprise, he said. What happened in Long Binh was typical of what was happening across the country.

The U.S. had completely underestimated the strength of the North Vietnamese Army and Vietcong guerrilla forces from South Vietnam, he said. It came as a shock to the American public and turned public opinion against the war.

One of the myths of Tet, he said, is that it was a big enemy military victory, he added. It wasn't. "Our military actually did very well considering."

Erik B. Villard, a historian with the U.S. Army Center of Military History, said there were other myths about Tet, some of which he wrote about in his Center for Military History book, "Combat Operations: Staying the Course, October 1967 to September 1968."

One myth, he said, was that the North Vietnamese orchestrated a number of major battles prior to Tet in the autumn of 1967 to draw U.S. forces away from the cities so they would be in a better position to succeed in capturing the urban areas.

The real story is more interesting, he said. The 1967 battles were local and regional campaigns, planned over the spring and summer of that year.

The idea for the Tet Offensive did not even occur to the enemy at the time, as their strategic planning process tended to be short-term and at times very chaotic, he said.

Also, why would they want to launch a major battle in November 1967, just months before Tet when full strength would be needed? There wouldn't be adequate recovery time, he said, noting that the National Archives provided some key documents he used in his research.

A second myth, Villard said, was that Gen. William Westmoreland, the commander of American forces in Vietnam, "was wedded to this notion of victory through attrition; that the way to succeed was to kill enough of the enemy that you crossed this imaginary threshold and you could just kind of grind your way toward success.

"Westmoreland deserves far more credit than he's gotten in my view," he added.

He was a shrewd person who understood the value of pacification and cutting enemy supply lines, as he was doing in secret operations to cut the Ho Chi Minh Trail, Villard noted.

A third myth, he said, is that U.S. military policy changed when Westmoreland was replaced by Gen. Creighton Williams Abrams Jr. in June 1968, in the middle of the Tet Offensive.

Abrams and Westmoreland saw mostly eye-to-eye on strategy, he said. The mission continued to be defending bases and lines of communication, as well as air interdiction operations and supporting pacification.

Pacification was a term used at the time to denote counterinsurgency operations, which included advise and assist missions and winning over the loyalty of the local population.

Policy didn't actually change until after mid-1969 when Vietnamization took hold, he said. Vietnamization consisted of drawing down U.S. forces and transferring responsibility to the South Vietnamese forces.

The buildup of forces into 1968 and the draw down a year later had already been planned on Westmoreland's watch, he said.

Merle L. Pribbenow II, an author specializing in the Vietnam War, with five years of service in Vietnam during the war as a CIA operative, said that a widespread myth was that the Tet Offensive was a well planned and executed enemy attack.

That's completely false, he said, referencing documents and interviews of NVA and VC commanders after the war.

Many of those generals became bitter with the way they and their units were treated by their own military and political leaders and the high numbers of casualties that resulted, he said.

"We focus on how we felt Army commanders screwed up and were unprepared. [The North Vietnamese] were saying the exact same things again and again," he said.

After the war, the Vietnamese did tactical reviews and battle studies, just as the U.S. Army did, to learn lessons and assess strengths and weaknesses, he noted.

The takeaway from that assessment, he said, was that the communists acknowledged that a lot of the poor decision-making during Tet resulted from underestimating U.S. military response, as well as the loyalty of the South Vietnamese people.

Like the Americans, the communists also inflated their own body counts, minimized their failures and exaggerated their accomplishments, he said.

The biggest problem, he added, was that shortcomings were not reported up the chain of command and authorities refused to listen to subordinates.

As a result of the assessment, he said the military leadership of Vietnam decided on a new approach. From then on, leaders were instructed to encourage subordinates to tell the truth, even if it wasn't something they wanted to hear or went against their own thinking.

Gregory Daddis, an associate professor of history and director of Chapman University's Master of Arts program in War and Society, said another myth was that the U.S. media was to blame for the lack of political will after the Tet Offensive.

There's a tendency, he said, to find someone to blame when a bad outcome occurs.

Looking back 50 years ago to the Tet Offensive gives everyone an opportunity to gain a better perspective on everything that took place, he said.

An important takeaway from Tet, he said, is that sometimes military action might not be the best tool in all situations to achieve the desired political effect.

Hagel added that "in the end, war is determined not by military might but by the support of the people. We found ourselves on the wrong side of that."

He concluded: "The sacrifices made by over 56,000 Americans who lost their lives and hundreds of thousands of individuals who were wounded, and all who served, were never really given much recognition for an assignment they didn't choose. But they served and they served honorably, and did what their country asked them to do. And I think that's a part of this story that needs to be told more often."