Former supervisor Dan White was found guilty today of two counts of voluntary manslaughter for the killings of Mayor George Moscone and Supervisor Harvey Milk last Nov. 27.

The verdict came at 5:40 p.m., after nearly 36 hours of deliberation, and was a major victory for the defense. Mary Ann White, his wife, embraced her sister-in-law, Nancy Bickel, and the two sobbed and shook while the verdict was read. White bowed his head and cried.

White faced charges of first-degree murder under circumstances that could have brought the death penalty. Instead, he faces a maximum jail term of less than eight years, and a minimum of 32 months. That sentence includes two charges of using a gun, for which he was also convicted.

Judge Walter F. Calcagno thanked the jurors for their service and ordered them back to the jury room where they voted not to talk to the press. Police were alerted to respond immediately to the jurors' homes.

Defense attorneys had sought to portray White, who had been a former fireman and policeman in addition to being elected supervisor, as mentally unbalanced. They said he was incapable of deliberating, premeditating or forming malice, the key requirements of murder. After 10 days of testimony and six days of deliberation, the jury agreed.

The verdict came on the eve of the birthday of Milk, the city's first openly gay elected official and a man who had citywide popularity, as did the mayor. The jury's decision brought a swift and angry protest.

About 1,800 marchers gathered in the predominantly gay Castro area within minutes of the verdict, and the crowd doubled in size by the time it reached City Hall two miles away.

Chanting "Remember Harvey" and "Dump Dianne" - a reference to Mayor Dianne Feinstein, Moscone's successor - the crowd surged against the ornate doors of City Hall and began beating on them.

By 8:45 p.m., police inside had already smashed windows alongside the doors to get out and help beleaguered colleagues. Other glass in and around the doors was smashed by the demonstrators.

Police later fired tear gas in an attempt to disperse the crowd, which had grown to an estimated 5,000. During a clash, Supervisor Carol Ruth Silver suffered a mouth injury when struck by a rock hurled from the crowd.

Several trash fires were set and police cars and other vehicles outside City Hall damaged. A number of other cars were burned in the area as the clashes between protesters and police continued.

The jury reportedly reached agreement on Moscone's death first, but struggled to reach a verdict on Milk.

"I think this is a sad way to end a tragic chapter in our history," said District Attorney Joseph Freitas. "I hope no segment of our city will act out in a way that does destruction to our city.

"I think the jury was swayed by the emotion interjected into the case by defense attorney Douglas Schmidt. They were swayed by the presence of the family of Dan White. We could not bring in the family of the mayor or Harvey Milk. That's not relevant."

Prosecutor Thomas Norman, who argued the case, sat tight-lipped as the verdict was delivered. Referring to the string of mental health experts presented by the defense, Norman said, "I really didn't find the shrinks' evidence very strong. Perhaps, and I say perhaps, the evidence of the psychiatrists gave them something to hang on."

The defense predictably disagreed. "It's the verdict that the facts supported," declared defense counsel Schmidt. He said White "is in very bad condition right now."

"Dan, to my mind, is guilt-ridden. I think he's not reacting to much of anything."

In the end, the verdict reflected the jury's decision that White was unable to form malice aforethought. Under California law, there cannot be a murder unless malice is present. The defense successfully argued that White was distraught from political, family and financial pressures, and that he suffered a "vile biochemical" mental illness called manic depression. These factors, plus his "frustration" and "rage" at Moscone's decision not to appoint him to the seat he had himself vacated by resignation, led to his being out of control on the day of the killings, the defense argued.

White was voted to the Board of Supervisors, San Francisco's 11-member governing body, in 1977 during the first election of supervisors by district. He represented a largely working class, predominantly white district where three-fourths of the people earn under $15,000 a year and two-thirds own their own homes.

White campaigned on a law-and-order platform, telling his supporters, "We're got to stand up to the criminal element in this city." He also favored the death penalty, and when 75 percent of San Francisco's voters rejected a state-wide death penalty ballot measure, only four precincts in the city voted for it - all of them in White's District 8.

His problems began after his election when the city attorney ruled that he could not hold jobs as both a fireman and supervisor. The news apparently came as a blow to the White family. His wife, pregnant, was forced to quit her teaching post. White joined his campaign manager in opening a new business but had to take a second mortgage to finance the venture.

On Nov. 10, 1978, White resigned abruptly, not bothering to notify even his wife first. He was pressured to reconsider by friends, family and political associates, and four days later asked Moscone for his job back. The mayor at first agreed, but later wavered.

Political pressures, apparently aided by Milk, were brought upon the mayor not to appoint White. By Nov. 27, it seemed apparent to everyone except White that he would not get the job.

On the morning of the killings, he went to City Hall with a .38-caliber revolver and confronted the mayor asking for reasons for his action. Rebuffed and angered, he killed Moscone with four shots, two to the head, and moments later did the same to Milk.

He then fled, called his wife and surrended to police.

The defense constructed a careful case, centered on the taped confession that moved many listeners to tears. The defense also made studious examination of the judge's instructions in an effort to have many altered to White's benefit. CAPTION: Picture, DAN WHITE . . . a victory for the defense