Mary Bonauto, the local attorney who was instrumental in fighting for same-sex marriage here in Massachusetts, took that fight before the U.S. Supreme Court Tuesday.

Bonauto, who is the civil rights project director at the Boston-based Gay & Lesbian Advocates & Defenders (GLAAD), delivered oral arguments that could make same sex marriage legal in all 50 states in the country. The court, according to The Boston Globe, is considering whether state bans on same sex marriage violate the U.S. Constitution’s guarantee of equal protection.

Reuters reported five of the justices, asked her why the court should change a definition of marriage that has existed for millennia, rather than allowing American voters to decide. CNN reported the court was “divided” over the issue Tuesday.

Bonauto was lead counsel in the landmark case Goodridge v. Department of Public Health, which is the case that made Massachusetts the first state in the country to legalize gay marriage in 2004.