Oscar-winning screenwriter Dustin Lance Black clearly remembers the moment he saw Joe Biden “searching his soul” about marriage equality — a moment that’s one of the reasons he’s now supporting Biden for president.

In the spring of 2012, when President Barack Obama and his vice president, Biden, were seeking a second term, Black was attending a campaign event at the home of gay entertainment executive Michael Lombardo, where Biden was the guest of honor.

Chad Griffin, who like Black was involved in the court fight against California’s anti-marriage equality Proposition 8, asked Biden if he supported equal marriage rights. Biden considered for a full minute before answering, and Black says he could see that the vice president was doing a lot of soul-searching. The answer was yes — and this was a few days before Biden made his public statement endorsing marriage equality on Meet the Press, and before Obama came out for equality as well.

“It’s never a good idea politically to get ahead of your boss,” Black tells The Advocate now, in an exclusive interview. But Biden “came out for marriage equality in that room in front of us. He knew it was the right thing to do.” The following weekend, Biden did his historic Meet the Press interview, and Obama endorsed marriage equality shortly afterward.

That’s a key reason but not the only reason Black, the screenwriter of Milk and When We Rise, is supporting Biden for president. He also sees Biden as a coalition-builder, and a coalition, perhaps a bipartisan one, will be needed to get the Equality Act through the U.S. Senate and to the president’s desk. The sweeping LGBTQ rights measure has passed the Democratic-controlled House but is stalled in the Republican-majority Senate. “I want to see the Equality Act passed in the next four years,” Black says.

“I’m all for big dreams and big ideas,” he adds. “I know there’s another candidate in this race who has big ideas. But Biden has the ability to create the alliances that are necessary.”

That candidate, U.S. Sen. Bernie Sanders of Vermont, is “a good man,” says Black, who promises to support Sanders if he’s the Democrats’ nominee — and he hopes Sanders’s supporters will do the same for Biden if he wins the nomination. But Sanders’s proposed revolution doesn’t seem to be gaining traction, Black says, and “big ideas die without good strategy.”

Black hasn’t supported Biden during the entire campaign. He was initially behind the history-making campaign of gay candidate Pete Buttigieg, the former mayor of South Bend, Ind. Black was very impressed with Buttigieg, and with the candidate’s husband, Chasten, who came to a Democrats Abroad event in London, where Black lives with his husband, Olympic diver Tom Daley, and their son, Robert Ray. “I don’t think we’ve seen the last of him,” Black says of Buttigieg.

Buttigieg dropped out of the presidential race Sunday, and the following day he endorsed Biden. But Black says that wasn’t why he got behind the former vice president.

“I’m not one to just follow the leader,” he says. “I’m a political geek. I watch the numbers; I want to know the facts.” The Democratic field this year has had a wealth of “dedicated, sincere candidates” who support the LGBTQ community, he notes.

In choosing Biden, “I’m leading with my heart and leading with my head,” he says. “I’m happy to turn my enthusiasm for Mayor Pete in Joe Biden’s direction.”

In addition to the 2012 event, Black has interacted with Biden several other times. The first time they met was when Black was visiting the White House while working on his 2011 film J. Edgar, about the late, infamous, and possibly gay FBI director J. Edgar Hoover. Biden approached Black and started telling him stories about Hoover, just to make sure the filmmaker had the facts.

“If you know politicians, rarely do they want to connect on a very personal level and spend time with you,” Black says. But Biden did. “To meet Joe Biden is to love him,” the screenwriter adds.

He knows Biden hasn’t always been an unequivocal supporter of LGBTQ rights. As a U.S. senator from Delaware, Biden voted for the anti-marriage equality Defense of Marriage Act in 1996, and in 1993 he supported the law that established the “don’t ask, don’t tell” policy for gay, lesbian, and bisexual people in the military — a policy that was supposed to make it harder to discharge them, but it didn’t.

“Has Joe Biden been perfect? Absolutely not,” Black says. But Biden has been willing to listen, to learn, and to grow, he adds.

He plans to work hard for any Democratic presidential nominee. As soon as he and Daley return from the Summer Olympics in Tokyo, Black says he’ll be in the Rust Belt campaigning for his candidate, and if the general election race is close his home state of Texas, he’ll go there too. “There is nothing more powerful than simply sharing the message of your candidate,” he says. He’ll also help raise funds.

Black remains busy with his film and TV career. He is working on a feature film for Netflix about African-American civil rights leader Bayard Rustin, “probably the first LGBTQ hero I came to know.” His producing partner on that is no less than Barack Obama, through the former president’s Higher Ground production company.

Black is also adapting Jon Krakauer’s nonfiction book Under the Banner of Heaven, about a double murder in a Mormon fundamentalist community, as a 10-part miniseries for FX. And he’s doing a documentary for Live Nation on the queer roots of rock and roll.

But he will most likely put those projects on hold for at least a few months leading up to the general election in November. This is no ordinary election, he notes.

“We want to be able to come back home and have a White House that’s sane again,” Black says. “Donald Trump has a really good chance of winning another four years. That will be devastating for most minority communities. It will certainly be devastating for the LGBTQ community.”