Olson argued that same-sex marriage is “a part of the right of privacy, association, liberty, and the pursuit of happiness.”

“The procreation aspect, the responsibility or ability or interest in procreation is not a part of the right to get married,” he added.

“I’m not sure that it’s right to view this as excluding a particular group. When the institution of marriage developed historically, people didn’t get around and say, ‘Let’s have this institution, but let’s keep out homosexuals.’ The institution developed to serve purposes that, by their nature, didn’t include homosexual couples,” said Chief Justice John Roberts.

“When did it become unconstitutional to exclude homosexual couples from marriage? 1791, 1868, when the 14th Amendment was adopted?” Scalia asked.

“May I answer this in the form of a rhetorical question?” Olson said. “When did it become unconstitutional to prohibit interracial marriages? When did it become unconstitutional to assign children to separate schools?”

Scalia and Olson went back and forth on this point, with Olson stressing same-sex marriage “was constitutional when we, as a culture, determined that sexual orientation is a characteristic of individuals that they cannot control.”

“I see. When did that happen? When did that happen?” Scalia asked.

“There’s no specific date in time. This is an evolution,” Olson responded.

“Well, how am I supposed to know how to decide a case, then, if you can’t give me a date when the Constitution changes?”

“The case that’s before you today is whether or not California can take a class of individuals, based upon their characteristics, their distinguishing characteristics, remove from them the right of privacy, liberty, association, spirituality, and identity that — that marriage gives them,” argued Olson. “It is not an answer to say procreation or anything of that nature because procreation is not a part of the right to get married.”

“Same-sex couples have every other right. It’s just about the labels,” Roberts offered. “…All you’re interested in is the label and you insist on changing the definition of the label.”

“It is like you were to say you can vote, you can travel, but you may not be a citizen. There are certain labels in this country that are very, very critical,” Olson said.

“I can accept that the state has probably an overbearing interest on protecting a child until they’re of age to marry, but what’s left?” Sotomayor asked.

“You’ve said in the cases decided by this court that the polygamy issue, multiple marriages raises questions about exploitation, abuse, patriarchy, issues with respect to taxes, inheritance, child custody. It is an entirely different thing. And if you — if a state prohibits polygamy, it’s prohibiting conduct,” the lawyer answered. “If it prohibits gay and lesbian citizens from getting married, it is prohibiting their exercise of a right based upon their status.”

Kennedy said “the problem with the case is that you’re really asking, particularly because of the sociological evidence you cite, for us to go into uncharted waters.”

Solicitor General Donald Verrilli Jr. chimed in on the side of Prop. 8 opponents to argue the measure “denies gay and lesbian persons the equal protection of the laws.”

“But what is your response to the argument which has already been mentioned about the need to be cautious in light of the newness of the — the concept of — of same-sex marriage?” asked Justice Samuel Alito. “…It may turn out to be a good thing; it may turn out not to be a good thing, as the supporters of Proposition 8 apparently believe. But you want us to step in and render a decision based on an assessment of the effects of this institution, which is newer than cellphones or the Internet? I mean, we — we are not — we do not have the ability to see the future.”

Verrilli said Prop. 8 “pushed a delete button” on even the prospect of same-sex marriage in the future with a “permanent ban.”

“The rest of the country has been cautious,” Scalia noted.

“Waiting is not a neutral act. Waiting imposes real costs in the here and now,” Verrilli said. “It denies to the — to the parents who want to marry the ability to marry, and it denies to the children, ironically, the very thing that petitioners focus on is at the heart of the marriage relationship.”

“It seems to me that your position that you’re supporting is somewhat internally inconsistent. We see the argument made that there’s no problem with extending marriage to same-sex couples because children raised by same-sex couples are doing just fine and there’s no evidence that they’re being harmed. And the other argument is Proposition 8 harms children by not allowing same-sex couples to marriage. Well, which is it?” Roberts asked.

“Their parents cannot marry, and that has effects on them in the here and now. A stabilizing effect is not there. When they go to school, they have to, you know — they don’t have parents like everybody else’s parents. That’s a real effect, a real cost in the here and now,” Verrilli argued.

A few lawmakers jumped into the public debate today, though many seemed to be exercising the same degree of caution discussed from the bench.

Tomorrow, the Supreme Court hears arguments in the Defense of Marriage Act challenge, a law a bit closer to the heart of the Hill than a California ballot measure.

“Proposition 8 and DOMA serve only to codify discrimination in our laws and perpetuate the prejudiced notion that lesbians and gays are to be treated differently than everyone else,” said Rep. Alcee Hastings (D-Fla.). “The fact of the matter is that they prevent same-sex couples from having the same critical rights, benefits, and protections that heterosexual couples receive through marriage.”

“The Constitution never contemplated marriage being anything other than between a man and a woman,” said Rep. Steve King (R-Iowa). “And for the United States Supreme Court to come to an opposite conclusion would mean, I think, a real distortion of the Constitution, which is a contractual guarantee between each of the generations.”