David Mixner, Fierce Fighter for Gay Rights, Is Dead at 77

David B. Mixner, a political strategist who played prominent roles in the anti-Vietnam War movement and in the arduous fight for gay rights, and whose decades-long influence with Bill Clinton spanned both eras, died on Monday at his home in Midtown Manhattan. He was 77.

The cause was complications of long-term Covid, said Steven Guy, a close friend.

Mr. Mixner, born three days apart from Mr. Clinton and raised in similar rural privation, met the future president when they were in their early 20s. He later arranged for Mr. Clinton to make the first public address by a major presidential candidate to a gay and lesbian audience, in 1992.

His political savvy was such that he was able to persuade California’s foremost conservative, Ronald Reagan, to oppose a 1978 state initiative to ban gay schoolteachers. The defeat of the measure was at that point the most significant win for gay rights in the country.

“When I met him when he was young,” Mr. Clinton said of Mr. Mixner in 1999, addressing an L.G.B.T.Q. group, “I thought I’d never met a person whose heart burned with the fire of social justice so strong.”

Mr. Mixner, the son of a farmworker in South New Jersey, dropped out of college to work as a political organizer, and in the late 1960s he seemed to be everywhere, including as part of Eugene McCarthy’s presidential campaign in 1968 and as a presence at the Democratic convention in Chicago that year. He was one of four national co-chairs of the Moratorium to End the War in Vietnam, a series of major protests in the fall of 1969.

Mr. Clinton met Mr. Mixner at a retreat for moratorium supporters on Martha’s Vineyard that year. The two men bonded during a walk on a beach, in part over their humble backgrounds, which set them apart from the upper-middle-class Ivy League students who were prevalent in the antiwar movement.

Mr. Clinton, an Arkansas native and a 23-year-old Rhodes Scholar studying at Oxford at the time, slept on Mr. Mixner’s couch when he visited the moratorium offices in Washington. He volunteered to help with a satellite protest at the American embassy in London. Mr. Mixner later visited him in Oxford, bunking on the floor of a house that Mr. Clinton rented.

As a Democratic insider at a time when almost all gay people in politics were closeted, the 1960s and early ’70s, Mr. Mixner dreamed of a public-service career but was convinced that his “terrible secret” of homosexuality would not permit it, he wrote in a memoir, “Stranger Among Friends” (1996).

So he largely took behind-the-scenes roles. In the 1970s, he moved to Los Angeles, bringing his organizing and strategic expertise to California politics. He worked on campaigns for Harvey Milk, the first openly gay candidate to be elected to San Francisco’s Board of Supervisors, and for the antiwar activist Tom Hayden. He was the campaign manager for Tom Bradley’s successful bid for re-election as mayor of Los Angeles in 1977.

While still largely closeted, Mr. Mixner in 1976 helped found the Municipal Elections Committee of Los Angeles, the first gay and lesbian political action committee in the country. Politicians at the time often returned money from openly gay donors.

Two years later, California Republicans, hoping to exploit a backlash against the nascent gay rights movement, placed Proposition 6 on the ballot: a proposal to bar gay men and lesbians from working in public schools.

The measure, also known as the Briggs Initiative (named after its sponsor, State Senator John Briggs), had wide support in polls. Mr. Mixner threw himself into opposing it. In a letter to friends, including Bill and Hillary Clinton, he disclosed that he was gay and asked for donations to fight the proposal.

It was Mr. Mixner who framed an argument for persuading Mr. Reagan to oppose Prop 6, according to the book “Out For Good: The Struggle to Build a Gay Rights Movement in America” by the reporters Dudley Clendinen and Adam Nagourney of The New York Times.

As a former Republican governor of California, Mr. Reagan was preparing to run for president as an anti-government conservative. In a meeting, Mr. Mixner made the case that the initiative wasn’t about rights for homosexuals at all; it was, he said, a question of government meddling and privacy and would open the door for disgruntled students to blackmail their teachers.

Mr. Reagan agreed and publicly voiced his opposition to Proposition 6. Overnight, public opinion turned. The initiative was soundly defeated.

The 1980s and early ’90s, the height of the AIDS epidemic, claimed many leaders of the gay rights movement, including Mr. Mixner’s romantic and professional partner, Peter Scott, who died in 1989. After years of inaction on AIDS by the White Houses of Mr. Reagan and his successor, George H.W. Bush, there were cautious hopes among L.G.B.T.Q. activists for the 1992 presidential election. Most gay and lesbian leaders favored Paul Tsongas, a liberal former U.S. senator from Massachusetts. But Mr. Mixner’s old friend Mr. Clinton asked him to raise money and build support in the gay community on his behalf.

At first, Mr. Mixner hesitated. “I said, ‘Bill, I’ve lost over 180 friends to AIDS,’” he told The New York Times in 1992. “‘Before I can get behind this campaign, I have to know where you stand on this, where you stand on AIDS and our struggle for our freedom.’”

An important issue for Mr. Mixner was ending the ban on gay men and lesbians serving in the military. In an interview in 2023 with Time magazine, he said he agreed to help Mr. Clinton on the condition that he would lift the prohibition.

In May 1992, Mr. Mixner introduced Mr. Clinton to 500 gay donors at a fund-raiser in Los Angeles. To raucous applause, Mr. Clinton said, “What I came here today to tell you in simple terms is, I have a vision and you are part of it.” He reiterated that he would end discrimination in the military based on sexual orientation.

But once in office, Mr. Clinton faced intense opposition to that plan. He compromised with a policy of “don’t ask, don’t tell,” which banned harassment of closeted gay soldiers while forbidding openly gay people to serve.

Mr. Mixner felt betrayed, and voiced his anger on the ABC News program “Nightline.” In his memoir, he detailed how he was frozen out by the Clinton administration for his criticism.

In July 1993, Mr. Mixner helped lead a protest over “don’t ask, don’t tell” outside the White House, where his arrest as a well-known “friend of Bill’s” received coverage in the news media.

He and Mr. Clinton eventually healed the rift. In a meeting in the Oval Office, Mr. Clinton jokingly said he had considered presenting him with a pair of handcuffs from his arrest, Mr. Mixner recalled in his book. (Congress lifted the military’s ban on gay men and women in 2011.)

David Benjamin Mixner was born on Aug. 16, 1946, in Salem County, N.J., the youngest of three children. His father, Ben, worked long hours on a commercial farm that grew and packed frozen vegetables. His mother, Mary (Grove) Mixner, was a bookkeeper for a John Deere tractor dealer.

Mr. Mixner is survived by a brother, Melvin.

In the fall of 1964, Mr. Mixner arrived as a freshman at Arizona State University and became swept up in political activism. He organized students to support a strike by local sanitation workers. Transferring to the University of Maryland, to be near the Washington hub of the antiwar movement, he volunteered as an organizer of the 1967 March on the Pentagon, where protesters chanted “hell no, we won’t go!” to Vietnam to fight.

He dropped out of college soon after and became a $320-a-month organizer for Mr. McCarthy’s presidential campaign.

Following the Clinton presidency, Mr. Mixner endorsed Barack Obama over Hillary Clinton in the 2008 Democratic primary. In 2009, he helped lead a march on Washington for equal rights, where he spoke along with Lady Gaga and Cynthia Nixon.

In 2008, when he received an award from the L.G.B.T.Q. advocacy group GLAAD, he recalled his life’s trajectory in an interview with the news website SFGate, expressing pride in his political activism but also striking a mournful tone about the toll of AIDS on his generation of gay men.

“All of my peers died of AIDS, and I have no one to celebrate my past or my journey, or to help me pass down stories to the next generation,” he said. “We lost an entire generation of storytellers.”