Retired New Hampshire Bishop V. Gene Robinson and his daughter Ella are among those who will speak later today at a rally in support of marriage rights for same-sex couples outside the U.S. Supreme Court.

“It’s so exciting to be a part of history in the making,” he told the Washington Blade on Monday afternoon. “For the Supreme Court it’s a time for them to decide if they’re going to be on the right side of history.”

Robinson, who became the Episcopal Church’s first openly gay bishop in 2003, will join Baltimore Ravens linebacker Brendon Ayanbadejo and others at the rally that will coincide with oral arguments in the case that challenges the constitutionality of Proposition 8. Rev. Al Sharpton, OutServe-SLDN Executive Director Allyson Robinson, Republican strategists Margaret Hoover and David Frum and National Council of La Raza President Janet Murguía are also expected to speak.

Robinson said he expects recent polls that indicate a sizeable majority of Americans now support marriage rights for same-sex couples could potentially influence the justices.

“They’re not stupid,” he said. “They know where this is going and do they want to be the last court that ruled against it or do they want to be the first court that ruled for it. It’s very exciting.”

Robinson said he remains “really confident” about the Defense of Marriage Act case on which the justices will hear oral arguments on Wednesday. He predicted a possible 6-3 vote against the 1996 law “because you can really argue it from a conservative stance that it’s the federal government messing in states’ business.”

“It would be a great thing if we could get something other than just a squeak by 5-4 vote,” Robinson said.

He added he expects a far narrower ruling in the Prop 8 case.

“I think they’re apt to rule narrowly just for California, but it will be a way of signaling to the country that marriage equality is on its way for everybody,” Robinson said. “Had they not taken it up, we would still not have known where they stood on that.”

New Hampshire is among the nine states and D.C. that currently allow same-sex marriage.

“It’s always helpful to us I think when a place that’s considered conservative comes out for marriage equality,” Robinson said. “Iowa and New Hampshire certainly qualify there.”

He added New Hampshire was the first state that “really figured out the power of restating the First Amendment rights for religious liberty” in a same-sex marriage bill — then-Gov. John Lynch in 2009 signed it into law. A bill that would have repealed the statute failed last March in the state House of Representatives by a 211-116 vote.

“New Hampshire was the first one that just restated what was already true, but put it there front and center that no clergy person would ever have to preside over such a service, no church would ever have to bless or authorize such a service,” Robinson said. “That has now been copied in all the succeeding states. It was just a powerful strategy and it just took a lot of the wind out of the sails of people who were saying oh they’re trying to force this down our religious throats.”