A new book provides a rare glimpse into something LGBT civil rights attorneys are loath to talk about: How much they bicker behind-the-scenes.

The book is Then Comes Marriage, about the high-profile litigation to end the Defense of Marriage Act (DOMA), which denied federal benefits to legally married same-sex couples. In the book, New York attorney Roberta Kaplan acknowledges bluntly how her effort to represent an elderly client, Edie Windsor, ran up against the effort of Boston-based Gay & Lesbian Advocates & Defenders (GLAD) to press two of its own cases.

One of GLAD’s cases was in Massachusetts, which comes under the U.S. Court of Appeals for the First Circuit, but the second case was in Connecticut, which comes under the Second Circuit. Kaplan’s case in Manhattan also fell under the Second Circuit. Once both cases got to the appeals level, she points out, they would be “in direct competition as to which case would get decided first.”

Publicly, attorneys for all the DOMA lawsuits maintained a veneer of camaraderie: It didn’t matter who got to the U.S. Supreme Court first as long as one of them got there and DOMA was struck down.

That veneer cracked in May 2009, just as Kaplan was putting her lawsuit together. GLAD and other national LGBT groups signed onto a press release warning, “Most lawsuits will likely set us all back.” At the time, most observers believed the press release was aimed at Ted Olson and David Boies and their federal lawsuit against the California state ban on marriage for same-sex couples. But Kaplan felt it was aimed at her, too.

“[I]f the major gay rights organizations had had their way, we never would have filed Edie’s lawsuit in the first place,” wrote Kaplan in Then Comes Marriage: United States v. Windsor and the Defeat of DOMA. In fact, the nation’s oldest and best-known LGBT litigation group, Lambda Legal Defense, declined to help Windsor. And the ACLU, which ultimately joined Kaplan, was hesitant at first, citing fear of stepping on the toes of the well-respected GLAD civil rights director Mary Bonauto. After leading the fight that propelled Massachusetts into becoming the first state to allow same-sex couples to marry in 2004, Bonauto had become a national marriage equality champion.

Kaplan said she decided not even to consult with Bonauto about her lawsuit.

“My fear was that Mary and I would get into an argument that might make the relationship difficult going forward,” wrote Kaplan. But to appease the ACLU, Kaplan did agree to delay filing her case in New York until GLAD was ready to file its case in Connecticut.

There were other political concerns behind-the-scenes, too. Kaplan had become sensitive to a growing discomfort among judges that some lawsuits –such as GLAD’s– were not simply advocating for one aggrieved client’s legal rights. They were carefully selecting a group of clients to advance a social and political agenda. And Second Circuit Chief Judge Dennis Jacobs was one of those judges.

With an eye on this attitude, Kaplan was determined to keep the focus of her lawsuit on “Edie Windsor and her tax payment –nothing more and nothing less.”

That was easier said than done.

First, Kaplan was suing the United States government for forcing Windsor to pay estate taxes on property Windsor shared with her late spouse, Thea Spyer. Under the law, women who survived their male spouses didn’t have to pay estate taxes. But because Windsor’s spouse had been a woman, the Internal Revenue Service demanded Windsor pay $363,000 in estate taxes. To help “Edie Windsor and her tax payment,” Kaplan would have to take down DOMA, a highly controversial and politically volatile law. And if DOMA was struck down, then the possibility of striking down state bans on marriage for same-sex couples around the country would become much more likely. The consequences of the lawsuit went far beyond Edie Windsor’s tax bill.

Second, as charming, attractive, and likeable as Edie Windsor was and is, “she was not shy” about speaking the truth in public about why her and Spyer’s relationship had endured more than 40 years: “Keep it hot.” Kaplan worried that kind of candor would have political consequences beyond the tax bill, too.

“As innocuous as that…phrase might seem,” wrote Kaplan, “I wanted the judges (and potentially Supreme Court justices) to see Edie and Thea’s relationship for its qualities of commitment and love, not for anything having remotely to do with their sex life. It just seemed safer that way.”

Meanwhile, the ACLU, worried Windsor’s image as a “privileged rich lady” was “not a story that’s going to move people.” The ACLU urged Kaplan to keep the $363,000 figure out of the press.

But Kaplan disagreed. Windsor’s wealth was modest by Manhattan standards. Plus, figured Kaplan, “What do conservative right-wingers dislike even more than gay marriage? Taxes.”

Both Kaplan and GLAD’s cases reached the Supreme Court at the same time, along with GLAD’s case from the First Circuit and another DOMA challenge from the Ninth Circuit. Both of GLAD’s cases involved groups of carefully selected clients and, newly minted Justice Elena Kagan had –while serving as Solicitor General– been involved in discussions about the GLAD case from the First Circuit. The California case, Golinski v. Office of Personnel Management, had not yet gone through the full appeal process.

Thus, it was Kaplan’s case the U.S. Supreme Court agreed to hear in March 2013. Many attorneys rushed to offer Kaplan advice on how to present her argument to the court. One even suggested she “de-gay” the case –advice she dismissed as “absurd.”

Kaplan also acknowledges that part of her argument before the Supreme Court “irked some in the LGBT rights community.” She told the justices that Edie Windsor should not have to pay the estate tax because New York recognized marriages of same-sex couples at that time. If Spyer had died in North Carolina or some other state that prohibited recognition of marriages between same-sex spouses, Kaplan conceded, then Windsor would have to pay the estate taxes.

“My job was to win Edie’s case,” explains Kaplan, “…not to make broader arguments about what position the Obama administration would or should take with respect to states like North Carolina that did not then have marriage equality….”

In the end, the U.S. Supreme Court struck down DOMA, and two years later, Kaplan sat in the Supreme Court as Bonauto argued the case to strike down state bans on marriage for same-sex couples.

Kaplan rightly accepts some of the credit for the fall of DOMA and the rise of marriage equality for herself and Edie Windsor. And she fairly acknowledges the contributions of so many others –legal activists, judges, plaintiffs, and family members– toward her success and the movement’s ultimate victory. Her willingness to write about the internal tensions within the LGBT legal community during one of its most historic struggles is both refreshing and instructive. Her decision to provide anonymity to most of her annoying critics is both noble and wise. Her ability to translate complex legal issues into the language of a non-attorney reader is impressive (and due at least in part to her “ghost writer” Lisa Dickey). And the personal journey she lays to bare –evolving from a painfully closeted conservative to a headline-making lesbian attorney activist— is a riveting drama that is, in and of itself, worthy of the read.