PORTLAND, Maine — Opponents and admirers alike have called Mary Bonauto the Thurgood Marshall of gay rights.

For decades Bonauto, 51, of Portland, has been a force at the center of many landmark cases dealing with gay rights, from Augusta to the chambers of the U.S. Supreme Court. In 2012, she successfully challenged the federal Defense of Marriage Act in the First Circuit Court of Appeals, and she coordinated all of the amicus briefs brought before the Supreme Court in a similar case, Windsor v. United States, which the court heard Wednesday.

“She’s the mastermind,” said Portland attorney Pat Peard, who has worked on gay rights cases with Bonauto going back to the 1980s. “I mean, Mary Bonauto is going to be in every legal textbook talking about civil rights in the United States. There’s not a doubt in my mind.”

It’s difficult to find a major gay rights battle in the northeast which lacks Bonauto’s involvement. She was there in Vermont when the state legalized civil unions for gay couples in 1999. Through Gay and Lesbian Advocates and Defenders, or GLAD, Bonauto argued Goodrich v. Department of Public Health, the case establishing the right to gay marriage in Massachusetts. And in Maine, Bonauto has had an indelible impact on issues of same-sex co-parent adoption, job discrimination and health insurance for domestic partners in her adopted state.

“Same-sex couples would not be married today except for the work Mary’s done,” said David Farmer, the director of communications for former Gov. John Baldacci. Farmer worked with Bonauto on the November referendum that legalized gay marriage in Maine. Farmer called Bonauto a “rock star.”

“I’m a huge fan of Mary,” he said.

It’s believed Bonauto’s case, Gill v. Office of Personnel Management, was not selected for a hearing by the Supreme Court because Justice Elena Kagan, who was solicitor general at the time, would have had to recuse herself from the proceedings.

“You’d have to be an inanimate object not to be disappointed,” Bonauto said of her case not being chosen. “But I really focused on the big picture, which is getting the issue to the Supreme Court and getting rid of DOMA.”

Bonauto has been widely recognized for her work. In 2004 the Boston Globe Magazine named her one of its people of the year. Bonauto and her wife, Jennifer Wriggins, a professor at the University of Maine School of Law, were featured on a list of the most powerful lesbian moms in the country. She’s been featured in several New York Times profiles, the most recent one published Wednesday, the same day she appeared on both MSNBC and PBS.

Happy to go into the legal intricacies of the Supreme Court, the cases she’s worked on and gay rights in general, she’s eager to change the subject away from herself and her reputation as a star within the gay legal advocacy community.

“Obviously there’s a nice element to being recognized,” she told the Bangor Daily News in an interview Friday. “But I can’t tell you how excited I am to get back to normal life. I’m really looking forward to going over homework and making dinner.”

Bonauto was quick to diffuse responsibility and highlight others she has worked with.

“It’s hard to be singled out, because this belongs to all of us,” she said. “I’m just so aware of how many people have been involved in these struggles.”

And her response to being compared to Thurgood Marshall, who argued the landmark racial equality case Brown v. Board of Education before the Supreme Court and later became the first African-American on the high court? “I just don’t find it so apt,” she said.

Even through the telephone, Bonauto exudes a quiet energy, speaking at a businesslike clip. But she makes no attempt to hide her passion for the cause to which she has dedicated her life since the beginning of her law career.

She studied law at Northeastern University, moving to Portland in 1987 for a job with the law firm MittelAsen. In 1990, Bonauto and her partner — now her wife — Wriggins relocated to Boston so Bonauto could take a job with Gay and Lesbian Advocates and Defenders, an organization she has worked for ever since. Wriggins later began working as a professor at the University of Maine School of Law and Bonauto returned to Portland for good in 2002, shortly after the couple’s twin girls were born.

Bonauto spoke lovingly of her family and her wife’s role in her career successes.

“For me, none of this would have been possible without my spouse Jenny Wriggins,” she said. “We both try to be parents 110 percent, but she really steps up in the midst of her own very demanding job.”

She said she’s seen Maine undergo immense change since her first years in Portland during the confusing, frightening early years of the AIDS epidemic. Bonauto — who was out as a lesbian both in her workplace and to her family — found her first advocacy amid the fear and uncertainty of that time.

“You have to remember, this was a different era,” Bonauto said. “But I was able to help people. When people started getting fired from their jobs, I represented them and helped negotiate contracts. Helping people who were suddenly ill and needed a will and so on. There was so much fear, but year by year the culture has changed.”

And having worked on legal cases related to gay rights since the 1980s, she’s had a privileged vantage point to observe how changing public opinion has affected the viability of initiatives like gay marriage.

“Time changed people’s minds because they realized they had common ground,” she said. “It was really important for them to see friends and family standing with us. That life goes on and communities become stronger.”

Since her earliest days practicing law, Bonauto’s work in the northeast, and Maine in particular, has been prolific.

Friends and colleagues have said she is remarkable in her ability to mix wonky legal matters with an astute political strategy.

“Her sense of timing and her ability to gauge the political environment has helped incredibly in her ability to put forward these excellent legal arguments,” said Peard.

“Mary is just an incredible legal and strategic mind,” said Farmer. “She’s just so good at what she does, so critical, so important. She’s made Maine and New England, and she’s on her way to making the country, a much better place.”