Why did two former adversaries pair up to take on California's ban on same-sex marriage? Ted Olson and David Boies make their case to Ross Todd

No US lawsuit in recent history has been the source of more partisan rancour than Bush v Gore. It divided everyone, it seems, except the two lawyers who argued opposing sides of the 2000 case before the US Supreme Court: Theodore Olson and David Boies.

"When I was watching David on television explaining the positions he was advancing on behalf of Vice President Gore, no matter how much I disagreed with him, I found myself nodding my head," says Olson with a grin. "I thought that was really dangerous." Adds Boies of Olson: "In the Bush v Gore arguments you could sit back and really admire what [Ted] was doing and his command of the cases, his command of the facts, his ability to weave them together and to actually tell a story… but you couldn't actually enjoy it."

So when the two lawyers announced in May 2009 that they had teamed up to fight for same-sex marriage, it wasn't a pairing of bitter ideological enemies. Rather it was the culmination of a professional and personal relationship that bloomed over the past decade: shortly after Bush v Gore, Boies and his wife, Mary, accepted Olson's invitation to his swearing-in ceremony as solicitor general.

The two lawyers also shared a long embrace on stage in autumn 2001 as Olson presented Boies with an award from the Lab School of Washington DC for overcoming dyslexia. Their appearance together was "a tremendously emotional thing", says Olson, whose wife Barbara died in the 9/11 attacks. "It was like the crowd thought, 'If they're coming together, so can we'." The men and their wives – Olson has since remarried – have taken a pair of bike trips in Europe with a group that has included NBC news anchor Tom Brokaw, The American Lawyer founder Steven Brill and Bloomberg's Norman Pearlstine. On the professional front, Boies says, "Ted and I have wanted to do something together for some time."

The 'something' that has brought together the two 70-year-olds and their firms – Gibson Dunn & Crutcher and Boies Schiller & Flexner – is Perry v Schwarzenegger, a federal challenge to California's Proposition 8. The 2008 ballot initiative amended the state's constitution to say that "only marriage between a man and a woman is valid or recognised". Olson and Boies have asked the federal courts to strike down Prop 8, arguing that it violates the equal protection and due process guaranteed under the 14th Amendment.

The case – one of a few same-sex marriage cases currently in the courts that could potentially reach the Supreme Court – is the most closely watched that either lawyer has handled since their election showdown. And, one way or the other, it will shape their professional legacies. "I'm convinced that 45 years from now people will look back on the discrimination against gays and lesbians with the same kind of puzzlement that people in their 20s look back at what happened in the mid-1960s," Boies says.

The Prop 8 challenge has involved several unexpected twists. When Boies and Olson filed suit in San Francisco federal district court on 22 May 2009, they thought a ruling on their motion for preliminary injunction would create grounds for a quick appeal to the US Court of Appeals for the Ninth Circuit. Neither expected the case to go to trial. But Judge Vaughn Walker opted to hold a 12-day bench trial in January 2010. The judge handed them a victory in August 2010 with a 136-page opinion stating that the plaintiffs "demonstrated by overwhelming evidence that Proposition 8 violates their due process and equal protection rights".

On 6 December 2010, Olson and Boies finally got their date with the Ninth Circuit, splitting oral arguments before a three-judge panel at a two-and-a-half-hour hearing. The Ninth Circuit put the case on another detour from its trajectory toward the Supreme Court by asking the California state supreme court to clarify whether state law gives proponents of Proposition 8 standing to appeal Judge Walker's ruling. (The California governor, attorney general, and other Government defendants named in the lawsuit had declined to defend Proposition 8 in court.)

Whether proponents of the ballot initiative have standing to appeal Judge Walker's ruling is an issue that could determine the outcome of the case before the Ninth Circuit panel even considers the merits. If the state court finds that the proponents don't have standing, that would likely mean the end of Proposition 8. But it could also mean the case stalls out before reaching the Supreme Court.

The story of how Ted Olson joined the fight for same-sex marriage has taken on an air of folklore. The week after Prop 8 passed in the 2008 election, Los Angeles political strategist Chad Griffin met over lunch at the Polo Lounge in the Beverly Hills Hotel with a group that included actor and director Rob Reiner and Reiner's wife. Griffin, who came out in his late 20s, had spent election night watching California election returns on a laptop while President Barack Obama's victory speech played on television. Prop 8′s passage made it "impossible to join in any sort of celebration," says Griffin, who was a staff assistant in the Clinton White House press office at age 19. "The message [Proposition 8] sent to young gay and lesbian teenagers – closeted and otherwise – was devastating," Griffin says.

The lunch group was discussing what to do in response to the initiative when Kate Moulene, an acquaintance of the Reiners, stopped by and overheard the conversation. She later told the Reiners they should contact her former brother-in-law Ted Olson because he shared their views. Griffin says he quickly recognised that "if in fact this was something that [Olson] agreed with us on, he could be a very significant figure in terms of accomplishing equality." After an initial phone conversation with Olson, Griffin offered to meet with him at Gibson Dunn's Washington DC office in late November.

In DC, Griffin noted tokens of Olson's career around his office – a photograph of President Ronald Reagan; a mug full of white quills representing Olson's Supreme Court arguments, including dozens earned as President George W Bush's solicitor general. They were reminders, Griffin says, that "this is a guy that I never thought in my entire life that I would ever agree with on anything".

But over about 45 minutes, their conversation ventured from the suicide rates of gay and lesbian teenagers to what a federal constitutional challenge to Proposition 8 would look like. "It was an emotionally moving and very persuasive session," Olson says.

Olson, who grew up in California and went to the University of the Pacific as an undergrad and the University of California, Berkeley, for law school, says when he heard that Proposition 8 had been put on the state's ballot, it crystallised his thoughts and feelings on the issue of same-sex marriage.

Although Olson is an icon within the conservative legal movement, he leans libertarian and says he believes that religious convictions should not be the basis for civil laws. Olson says he thought it was wrong that fellow citizens who "are like us in every single way except for their sexual orientation [were] selected out to be denied a relationship… because of the way they were born," Olson says. "It seemed to be cruel and unnecessary and very harmful."

After his meeting with Griffin, Olson discussed the idea of taking the Prop 8 assignment with his wife, his children, Gibson Dunn chair Kenneth Doran and Los Angeles partner Theodore Boutrous, whom he would eventually tap as his field general in California.

From the beginning, Olson knew he would need co-counsel. He says he didn't want the case to "look like one moss-backed conservative person stepping out of character". Olson initially considered teaming up with prominent gay and lesbian lawyers. Early on he contacted Jenner & Block partner Paul Smith, who successfully argued Lawrence v Texas, the 2003 Supreme Court case that struck down Texas' sodomy law. Smith declined to play a role in the case.

When Olson called Boies in early spring 2009 about working on the case as co-counsel, Boies' deliberations were less exhaustive than his counterpart's. Boies "didn't even pause to take a breath before he said enthusiastically, 'Yes. Count me in. I'll do it'," Olson says. Boies says he still talked the case over with partners, but he was confident that they would be on board because of the firm's history of taking on large pro bono matters.

Boies says he started paying close attention to the issue of same-sex marriage after then San Francisco mayor Gavin Newsom directed city officials to issue marriage licenses to gay and lesbian couples in 2004. "Seeing those couples from around the country stand in line overnight," Boies says, "I thought to myself, 'Why would you want to prevent people from having something that is so important to them and costs us nothing?'"

Still, Boies initially had some of the same concerns about bringing the suit that some gay and lesbian advocates had – they believed that a loss in federal court could cause setbacks in the larger fight for equal rights. It took 17 years, after all, for the Lawrence case to overturn a prior sodomy ruling at the Supreme Court.

"That was fast for the Supreme Court," said nine gay and lesbian groups, including Gay & Lesbian Advocates & Defenders (GLAD) and Lambda Legal, in a statement titled Make Change, Not Lawsuits rereleased the same day Olson and Boies announced their lawsuit. "And during that time, many [lesbian, gay, bisexual, and transgender] Americans lost jobs, lost custody of their children, and suffered other harms because [the earlier] decision was taken as a licence to discriminate against us."

Boies says: "Because [those concerns] came from people who had really devoted an enormous amount of effort over a long period of time to this cause – that was something that we had to think about seriously." Boies, though, agreed with Olson that federal litigation challenging Proposition 8 was inevitable, and that any team bringing such a challenge should be well funded and experienced in the federal courts. "We had clients who wanted to get married, and we believed they had a constitutional right to get married," Boies says. "To say that they needed to wait until there was the 'right' time I don't think was something for any lawyer to do."

Between the autumn of 2008 and the spring of 2009, when Olson talked to Boies, political strategist Griffin raised money to found The American Foundation for Equal Rights (AFER), the non-profit foundation formed to fund the litigation. Gibson Dunn donated its first $100,000 (£62,000) of work on the matter, and since then the firm has negotiated flat fees periodically with AFER for the phases of the case that have followed. "It's more of a good-faith dialogue than a lockdown agreement," says Gibson Dunn's Doran. The arrangement has worked out to be an 80% discount off typical Gibson Dunn rates. At first, Boies Schiller agreed to take the case for a discounted fee, but later gave back an initial payment after deciding to do the work pro bono. For his part, Griffin says the assignment he envisioned was beyond the scope of a typical pro bono case – a multiyear, resource-intensive campaign to win marriage equality nationwide.

In spring 2009 a Gibson Dunn team including Boutrous; partners Christopher Dusseault, Ethan Dettmer and Matthew McGill; and associates Amir Tayrani, Theane Evangelis Kapur, and Enrique Monagas began doing legal research about marriage laws in California and other states and Supreme Court cases involving marriage, gay and lesbian rights, civil rights, due process and equal protection issues. "We didn't want someone else to file [another challenge in federal court] ahead of us and be the other case we had to compete with or be joined with, so that we would not have control of the litigation," Olson says. "That meant we had to be quiet."

Secrecy was of such importance that the client code and matter description in Gibson Dunn's internal system kept junior associates and paralegals who were assigned discrete tasks from knowing they were working on a federal challenge to Prop 8. (For instance, Monagas asked a junior associate to research where and how to serve the attorney general and governor of California with a lawsuit without describing the pending filing.)

Meanwhile, a separate challenge to Prop 8 brought by couples and municipalities made its way through the state court system. At oral arguments in March, a majority of the judges on the state supreme court seemed unlikely to strike down Proposition 8 on the basis of the plaintiffs' argument that it was a revision of the state's constitution rather than an amendment – a distinction that would have required approval of two-thirds of both houses of California's legislature prior to the November election. With the state supreme court set to rule within 90 days of arguments, Gibson Dunn lawyers began preparing filings. Los Angeles associate Kapur handled the first draft of the complaint and DC associate Tayrani drafted the first version of the preliminary injunction motion.

In late spring the team had a task remaining before finalising the papers and filing the case in federal district court: going with the plaintiffs to apply for marriage licences. On Wednesday, 20 May 2009, Gibson Dunn's Dusseault and Kapur went to the Los Angeles county clerk's office with plaintiffs Paul Katami and Jeffrey Zarrillo, a gay couple who had been together for nearly a decade. An employee at the clerk's office told the pair they could not be issued a licence.

The next day Gibson Dunn's Monagas accompanied Kristin Perry and Sandra Stier, lesbian partners who had been together for nine years and were raising four boys together, to the Alameda County Clerk-Recorder's office to obtain a marriage licence. (Perry is the same involved in Perry v Schwarzenegger. ) The initial worker they approached did not want to refuse them, so a supervisor read them a statement saying they could not be issued a permit because of Proposition 8. They were welcome to come back once the law changed, the supervisor said. Monagas, who married his husband in October 2008 in the brief window when gay marriage was recognised by California before the election, says he remembers thinking that day, "This is the first step toward marriage equality. It happened today. Right now."

The Perry group filed suit on Friday, 22 May 2009, after the state supreme court announced that its decision would be handed down the following Tuesday. As expected, the state court upheld Prop 8. The Perry team announced their federal challenge to the law on 27 May, at a news conference at the Millennium Biltmore Hotel in Los Angeles. The vast majority of lawyers at Gibson Dunn and Boies Schiller were surprised by the announcement. Even though Olson says the reaction to the filing was overwhelmingly positive, there were a small number of colleagues who disagreed with his constitutional argument.

In August, Judge Walker set a trial date for early 2010, and added new members to the Perry team as he allowed the city and county of San Francisco to intervene. The race to trial was on. The Perry team had four months to identify witnesses, file expert reports and take depositions. Gibson Dunn's Dusseault, Boies Schiller partner Jeremy Goldman, and San Francisco chief deputy city attorney Therese Stewart co-ordinated the effort through weekly conference calls. Stewart's office, which had worked on three prior same-sex marriage cases in California courts, had previously gathered expert declarations on relevant subjects. "We had put together a trial record of sorts and gotten all dressed up with no place to go," Stewart says. Four of the city's experts were retained by the Perry team.

In the run-up to trial, Boies travelled to Montreal in November 2009 to take depositions of two of the opposition's experts, Katherine Young and Paul Nathanson, both faculty members at McGill University. "I don't take a lot of depositions," Boies says. "In the Microsoft case I only did one deposition, which was of Bill Gates." But since the pair were "experienced advocates" who had participated in Canada's marriage debate, Boies says he "thought it was important to try and build as good a record for cross-examination as we could".

Boies Schiller counsel Rosanne Baxter tracked down the academics' writings and prior public statements and pulled out cogent quotes and concepts for Boies. Dyslexia keeps him from reading quickly, so he put together points that he wanted to make with the witnesses and asked Baxter for help digging up more material to support those thoughts. The opposition ultimately did not call the McGill faculty members at trial: the plaintiffs entered pieces of their depositions as evidence.

Boies' focus on the opposition continued at trial in January 2010 as he cross-examined both their experts and handled the only adverse witness. His confrontation with expert witness David Blankenhorn, founder and president of the Institute for American Values, proved contentious as it stretched out over two days. Blankenhorn had testified that gay marriage could contribute to an increase in divorce rates and the number of children being born out of wedlock. Boies' cross-examination elicited the admission from Blankenhorn that the children of gay couples would benefit from their parents' ability to marry. Blankenhorn also agreed with a statement he had previously written in his 2007 book The Future of Marriage stating that "we would be more American on the day we permitted same-sex marriage than we were on the day before".

Theodore Uno, a Boies Schiller associate who had joined David Boies at his first in-person meeting with AFER's Griffin in New York in 2009, says that being in the courtroom for the Blankenhorn cross-examination provided a unique blend of "the personal and the professional". Before Prop 8 passed, Uno had planned to get married to his partner, Derek Peake, with whom he is raising five children.

Where Boies' strength involves asking questions, the very nature of Olson's practice as an appellate lawyer entails being interrupted with them by judges. Olson writes out his arguments, or at least extended pieces of what he'd like to say, with a no. 2 Ticonderoga pencil. His assistant Helen Voss, who has worked with him for more than 20 years, types up drafts for him to review. This process can repeat upward of 50 times for each argument. "I want it to be as perfect as I can make it, because you may only have that one time to express that one point of view," he says. "You want people to hear it, understand it, agree with it."

Because of a pending appellate matter in the case, closing arguments in the district court trial weren't heard until June 2010, nearly five months after the last day of witness testimony. That delay gave Olson time to try out a new technique: he interspersed his closing argument with video of testimony recorded at the trial. Gibson Dunn's Monagas and Sarah Piepmeier scoured the trial transcripts for excerpts including emotional moments of the plaintiffs' testimony on the trial's first day. Boies had examined Katami and Zarrillo and Olson handled Perry and Stier. "I don't think that I could do anything in a closing argument more persuasive than playing the video that was taken of their testimony," Olson says. "That told an immense and powerful story."

Charles Cooper from Washington DC's Cooper & Kirk handled the opening and closing arguments at trial as well as the appeal for Prop 8 proponents. Solo practitioner Andrew Pugno and the Alliance Defense Fund were co-counsel. The crux of their argument, as summed up in their appellate brief, is that "responsible procreation and child rearing is the animating purpose of marriage". They argue that Judge Walker's decision effectively stripped the voters of California of the right to decide how to define marriage in the state.

Judge Walker ruled in favour of the plaintiffs on 4 August 2010. Twelve days later, the Ninth Circuit ordered the judgment stayed pending appeal. Olson and Boies first talked about how to split appellate arguments at the Ninth Circuit in September. After discussing several options in the intervening months, they went with their initial plan that Boies would argue the issue of whether their opposition had standing to appeal, and Olson would argue the merits of the case.

Preparations for the appellate argument included an afternoon moot court session a few days before in a conference room in Gibson Dunn's San Francisco offices. Eight colleagues gathered around tables littered with colour-coded case books and half-empty soda cans. Boies sat at a table to Olson's right with his eyeglasses perched on the tip of his nose, having just run through his argument in front of the group.

Olson began as he would three days later before the Ninth Circuit panel, arguing that California "carved discrimination on the basis of sex and sexual orientation into its fundamental governing charter". At the end of his prepared remarks, he countered the opposition's contention that allowing same-sex marriage would somehow cause children to become "prematurely occupied with issues of sexuality". That reasoning, Olson argued, "would warrant banning comic books, television, magazines, video games, the internet and, of course, contact with other children." The line elicited a round of laughter from the lawyers around the table.

The following Monday morning before the judges, Olson received a similar response from the packed Ninth Circuit courtroom with a tweaked punch line, changing "contact" with other children into the more Ninth Circuit-friendly "conversations with other children".

Talking about the change in language a month after the argument in January 2011 in his Washington DC, office, Olson didn't know whether to attribute the change to his process of revision or an off-the-cuff improvisation. While he's happy to discuss such minutiae, he's more interested in discussing the larger issues raised in the case and the four plaintiffs he's representing.

When this reporter asked Olson what comes next if Perry does not make it to the Supreme Court, Olson firmly focused on his clients in the present case. "Lawyers sometimes get caught up in what they want to accomplish and what their goals are," Olson says. "We represent four people whose lives are in our hands, in a sense. We want them to have their goal. We want them to be married and to be treated as equals in California… we can't forget that we're representing human beings."

This article first appeared in The American Lawyer, a US affiliate of Legal Week.