Allies of MassEquality gather to encourage support of marriage equality in light of the United States Supreme Court justices discussing the historic cases of Proposition 8 and the Defense of Marriage Act (DOMA) on Tuesday and Wednesday. Democratic U.S Senate candidate Edward J. Markey, who is endorsed by MassEquality, also spoke at the Tuesday rally.

As the U.S. Supreme Court began hearing oral arguments on same-sex marriage on Tuesday, at Harvard and in the Boston area, advocates demonstrated support for marriage equality.

In an advocacy movement initiated by the Human Rights Campaign, Facebook users across the country changed their profile pictures to red equal signs meant to indicate that same-sex marriage is equal to straight marriage. William F. Poff-Webster ’14, the Vice President of the College Democrats of Massachusetts who is also an inactive Crimson editor, was among them.

“This is one of the important changes that my generation can make to help improve society,” he said. “I wanted to show my support.”

In Boston, activists decked out in rainbow colors gathered on City Hall Plaza for a rally hosted by MassEquality, a group that fights against discrimination on the basis of sexual orientation, gender identity, and gender expression.

Menino greeted ralliers with an enthusiastic speech, saying that American ideals of equality demand that gay couples enjoy the same rights as straight couples.

“Supporting marriage equality has always been an easy call for me,” Menino said. “It should be an easy call for the Supreme Court today, and tomorrow.”

Christopher K. Frost ’14-’15, who is taking time off from Harvard to work as an intern at the Center for American Progress, attended the rally.

“The most important and significant part of the rally was people responding to the anti-equality rally sponsored by the National Organization for Marriage,” he said, referring to a march that took place in Washington, D.C., on Tuesday. “The response to their false claims about the lesser value of same-sex relationships was both respectful and powerful.”

Both demonstrations came in response to the start of the Supreme Court cases on same-sex marriage.

Tuesday’s case is an appeal of a lower court’s decision on the constitutionality of California’s Proposition 8 which banned same-sex marriage. On Wednesday, the Supreme Court will address a case challenging the 1996 Defense of Marriage Act, a federal law that defined marriage as between one man and one woman.

Ivel Posada ’14, one of the co-chairs of the Harvard College Queer Students and Allies, did not attend the rally. He chose to review the case and listen to the Supreme Court oral arguments on his own.

“I’ve been watching the gay marriage cases since I was little,” he said. “It’s always something I experienced alone.”

Posada was disappointed by the oral arguments, saying he thinks it seems like the Supreme Court will dismiss the case and rule on it very narrowly. But, like Frost, he was hopeful about Wednesday’s case and for the future of marriage equality.

“We’ll probably have a lot more luck there,” Posada continued, “because it doesn’t raise the question directly of the constitutional right of gay marriage.”

—Yen H. Pham contributed to the reporting of this article.

—Staff writer D. Simone Kovacs can be reached at dkovacs@college.harvard.edu. Follow her on Twitter @simkovacs.