Supreme Court Justice Anthony Kennedy Says Definition of Marriage as One Man-One Woman Has 'Been With Us for Millennia'

(Photo: Reuters/Joshua Roberts)Supporters of same sex marriage rally in front of the Supreme Court before the court hears arguments about gay marriage in Washington, April 28, 2015. The nine justices of the Supreme Court began on Tuesday to hear arguments on whether the Constitution provides same-sex couples the right to marry, taking up a contentious social issue in what promises to be the year's most anticipated ruling.

U.S. Supreme Court Justice Anthony Kennedy, considered by experts to be a "swing vote" in the gay marriage case that's expected to split the justices in a five to four decision, made statements both for and against same-sex marriage during Tuesday's oral arguments.

"The word that keeps coming back to me is 'millennia,'" Kennedy told Mary Bonauto, a lawyer for the same-sex couples challenging state laws that prohibit same-sex marriages. "This definition has been with us for millennia. It's very difficult for the court to say, 'Oh well, we know better.'"

Later in the day, however, Kennedy said that same-sex couples were seeking the same "dignity" and "ennoblement" as heterosexual couples.

Kennedy, along with Chief Justice John Roberts, asked tough questions to plaintiffs and the defense during the two and a half hour arguments in Obergefell v. Hodges.

At one point, Roberts told a lawyer for the same-sex couples, "you're not seeking to join the institution — you're seeking to change what the institution is. The fundamental core of the institution is the opposite sex relationship and you want to introduce into it a same-sex relationship."

Lawyers argued before the justices whether the U.S. Constitution requires states to permit same-sex couples to marry. The nine-member court agreed to hear arguments for and against same-sex marriage based on four cases from the U.S. Court of Appeals for the Sixth Circut as part of the legal ruling process, which include: Obergefell v. Hodges (Ohio), Tanco v. Haslam (Tennessee), DeBoer v. Snyder (Michigan), and Bourke v. Beshear (Kentucky).

Donald Verrilli, a lawyer for the Obama administration, argued that "gay and lesbian people are equal, they deserve the equal protection of the laws, and they deserve it now," while urging the court not to wait on the ruling, which could come as early as June.

A lone Christian protester dramatically interrupted oral arguments during the first 90 minutes, shouting that "homosexuality is an abomination."

"'The Bible teaches that if you support gay marriage you will burn in hell for eternity,' he screamed, prompting Justice Antonin Scalia to joke that the interruption was 'rather refreshing,'" according to USA Today.

The protester was subsequently removed from the court room and handcuffed by police.

There are 12 states that still ban same-sex marriage, including Georgia, Ohio, Louisiana and Texas.