After the gunfire in Vietnam's jungles, the next devastating event in Joseph Zengerle's life was the neglect he said he felt when he returned to the United States.

It was 10 years ago, but he remembers his feelings vividly.

Still wearing Army fatigues, Zengerle boarded a plane from San Francisco to Dulles International Airport. "When I entered and dropped my bags," he said yesterday, "it was dead quiet on the airplane. Everybody was in there in civilian clothes. They just looked at me. I walked down the aisle to my seat and nobody talked to me. Nobody even smiled at me."

Zengerle, a West Point graduate who served as a special assistant to Gens. William Westmoreland and Creighton Abrams, was a participant-and perhaps a symbol-of the longest and most expensive war in America's history. That war and to a greater extent the men who served in it were subjects to be forgotten and avoided, Zengerle felt.

Two presidents since that time have asked the country to put the experience behind and to forge ahead.

But yesterday, on the eve of Memorial Day and the start of a week honoring Vietnam War veterans, Zengerle and other veterans called for a national period of remembrance and discussion about the veterans' needs and about the direction the United States should take based on lessons learned from the Vietnam War.

"The war was a painful experience for the entire country. It divided the country like nothing had since the Civil War," Zengerle said.

"Unconsciously, what many Americans did was transfer to the veteran their terribly justified feeling about the war," he said. "I believe the status now . . . is that we have allowed sufficient time to lapse so that the pain of the wartime experience has subsided. I believe it is now time for Americans to consciously understand what many of them were feeling unconsciously for so many years."

Robert Muller, a former Marine lieutenant who is paralyzed from the chest down from a bullet that severed his spine during a Vietnam battle, said it is time for Americans to ask those questions that were never asked and to reflect on the answers.

"We must ask ourselves, why did Vietnam happen? Why, when it seemingly became evident that it was an ill-advised action, were we not able to reverse ourselves?" said Muller head of the newly formed Vietnam Veterans of America, a group formed to press the case for veterans.

"People still have a problem with a feeling of guilt on many levels, but I hope that we as veterans can put the question and be the catalyst to come to terms with the questions," Muller said.

Muller said statistics and information gathered by his organization show that Vietnam veterans as a group suffer from high rates of suicide, divorce and mental breakdowns compared to the rest of the country.

A large percentage of veterans still make less than $7,000 a year, Muller said. He said few veterans took advantage of veteran educational benefits because, until 1974, those benefits were insufficiently low in some areas of the country to help veterans attend school.

According to a fact sheet on Vietnam veterans issued by the U.S. Conference of Mayors, there has never been an overall plan by the federal government to ensure that veterans are employed and that they receive adequate educational assistance and psychiatric care. Many veterans, the mayors' group said, were never honored or congratulated for entering the service in wartime.

"The average age of the Vietnam vet is 33," Muller said. "On the average, these guys came of age during the Kennedy period of 'Ask not what your country can do for you, [ask] what you can do for your country.' We had a presumption of seeing the government in a favorable light."

Muller said that, for many Vietnam veterans, there was a willingness to serve despite the growing knowledge that many would never return.

"If we can take lightly the . . . sacrifices that were made, especially by those who died, I think we are doing ourselves a tremendous harm," said Muller, 33, a lawyer.

Two days after Christmas in 1968 and about 10 days after he returned home to Washington, Zengerle walked around the streets of Southeast Washington at 2 a.m.

"I wanted somebody to mug me, to try to hurt me and I wanted to kick the hell out of them," Zengerle said. "I walked the streets for hours, wanting to release something, wanting to release emotions. But nobody attacked me."

Through the help of his wife Lynda and others, Zengerle said, he was able to begin to open up, to share emotions and to begin the painful experience of self-examination, a process that Lynda says they are still working on 10 years later.

Some veterans, Muller said, have never been able to discuss their feelings and emotions.

Zengerle, who is a lawyer now, says, "If we don't examine those experiences with eyes open, that experience will be manifested in distorted ways.

"Vietnam Veterans Week is not an end to what we went through in this nation for me and I hope the rest of the country, but a beginning in the process of national self-evaluation, to come to terms with that war and to recognize the vaule and the virtue of the men and women who fought in it." CAPTION: Picture 1, Volunteer Andrea Benarde pins ribbon on Vietnam veteran Sherman Green in Lafayette Park. By James M. Thresher-The Washington Post; Picture 2, Joseph Zengerle, who went through "painful experience" of the Vietnam War, poses with wife, Lynda, and their sons Jason, 5, and Tucker, 9 months. By Douglas Chevalier-The Washington Post