Joseph Landau, a former assistant managing editor at The New Republic, is an associate professor at Fordham Law School. He's covering oral arguments at the Supreme Court for The Stranger this week.

Today the court heard arguments in Hollingsworth v. Perry, which addresses whether California’s Proposition 8—a ballot initiative amending the state constitution to define marriage as solely between one man and one woman—violated the U.S. Constitution. As you probably know, a federal trial court struck down Prop. 8 as violating the guarantees of due process and equal protection under the U.S. Constitution. The state decided not to appeal the decision, and a group of private defenders stepped in to champion Prop. 8 and come to its defense.

The court spent considerable time on whether Prop. 8's private defenders have the requisite “standing” to appeal the decision. It then moved on to the constitutionality of Prop. 8 itself. It is never a good idea to make predictions about a case based on what one hears during the arguments, so I'm not going to do that. But there were some fascinating exchanges, and perhaps a few surprises, that I highlight below:

• The Justices seemed surprisingly cold to two distinctive middle-ground alternatives that the plaintiffs, several amici, and the U.S. government championed. The first of these arguments, often called the "one state" or "California only" solution, focuses on the Prop. 8's unique effect within the State of California—specifically, that it took away the right of same-sex couples to marry after the California Supreme Court ruled that the state constitution guaranteed them that right. (Eighteen thousand same-sex couples were married during that period, and those marriages remain in effect today.) The Ninth Circuit adopted this very rationale—perhaps in the hopes of appealing to Justice Kennedy. The second, slightly broader argument is that the nine states that currently provide comprehensive domestic partnerships or civil unions to same-sex couples—i.e., all the benefits of marriage without including those same-sex couples within the actual definition of "marriage"—place a badge of inferiority on them by excluding them from that critical institution. As Ted Olson, the lawyer for the plaintiffs, put it during oral argument, "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."

• Neither Justice Kennedy nor the other justices appeared to be persuaded by Olson's argument for a middle-ground solution. Instead, several of the justices seemed uncomfortable with a ruling that, on the one hand, states making some progress on gay rights (by providing domestic partnerships) would have to go all the way, while those providing no benefits get off scot-free. As Justice Kennedy put it, the Ninth Circuit "basically said that California, which has been more generous, more open to protecting same-sex couples than almost any state in the union, just didn't go far enough, and it's being penalized for not going far enough. That's a very odd rationale on which to sustain this opinion."

• Justice Kennedy asked whether the prohibition on same-sex marriage could "be treated as a gender-based classification," adding, "It's a difficult question that I've been trying to wrestle with." This is a meaningful question because it revives an issue that featured in the trial court's opinion but not in the Ninth Circuit's ruling. The argument, which gay-rights advocates have made for years, is that the exclusion of gay and lesbians from the institution of marriage imposes a kind of sex-based discrimination by prohibiting men from doing something that women are allowed to do (that is, marry a man), and prohibiting women from doing something that men are allowed to do (that is, marry a woman). Some LGBT advocates find the argument unsatisfying because it downplays the extent to which prohibitions on same-sex marriage are really about sexual orientation discrimination, yet the argument could have appeal because it builds on a body of Supreme Court cases that have held gender-based classifications to exacting scrutiny. Interestingly, the justices spent very little time asking questions regarding whether the Court should apply that same standard—known as "heightened scrutiny"—to sexual-orientation-based classifications, despite the fact that this argument has been championed by both the plaintiff couples and the federal government, both as an amicus in this case, and as a party in tomorrow's case, Windsor v. United States.

• Justice Kennedy asked about the children of same-sex couples.

This was in the course of discussing whether it is appropriate for California to proceed with caution by denying same-sex couples the right to marry until more sociological data is available regarding gay and lesbian families with children. Justice Kennedy noted that "there's substance to the point that sociological information is new.... On the other hand, there is an immediate legal injury or legal—what could be a legal injury—and that's the voice of these children. There are some 40,000 children in California... that live with same-sex parents, and they want their parents to have full recognition and full status. The voice of those children is important in this case, don't you think?” Indeed, despite all of the arguments made by Prop. 8 supporters that respecting the rights of same-sex couples to marry will somehow “redefine” the institution, or dilute it of its function as a providing a mechanism for the stability of families with children, there are thousands of counter-examples of happy, healthy, and loving families headed by two moms or two dads.

• Justice Antonin Scalia and Mr. Olson had the most stirring back and forth in all of today's oral arguments over the question of "when it became unconstitutional" to prohibit same-sex marriage. It began with Justice Scalia asking Mr. Olson: “I'm curious, when did it become unconstitutional to exclude homosexual couples from marriage? 1791? 1868, when the Fourteenth Amendment was adopted?... When—when—when did the law become this?" Olson answered this question rhetorically, asking, “When did it become unconstitutional to prohibit interracial marriages? When did it become unconstitutional to assign children to separate schools?"

Justice Scalia shot back: “It's an easy question, I think, for that one. At the time that the Equal Protection Clause was adopted... But don't give me a question to my question.” This drew laughter from the spectators. Justice Scalia continued, “When do you think it became unconstitutional? Has it always been unconstitutional?”

Mr. Olson: “When the California Supreme Court faced the decision, which it had never faced before"—the question of whether it was constitutional to exclude gays and lesbians from marriage.

Justice Scalia: "That's not when it became unconstitutional. That's when they acted in an unconstitutional matter—in an unconstitutional matter. When did it become unconstitutional to prohibit gays from marrying?”

Mr. Olson responded that the California Supreme Court "did not assign a date to it, Justice Scalia, as you know. What the court decided was the case that came before it...”

But Justice Scalia interrupted: "I'm not talking about the California Supreme Court. I'm talking about your argument. You say it is now unconstitutional.”

Mr. Olson: “Yes.”

Justice Scalia: “Was it always unconstitutional?"

Mr. Olson: “It was constitutional when we, as a culture, determined that sexual orientation is a characteristic of individuals that they cannot control..."

Justice Scalia interrupted again: “When did that happen? When did that happen?"

Mr. Olson: "There's no specific date in time. This is an evolutionary cycle."

Justice Scalia: “Well, how am I supposed to know how to decide a case . . . if you can't give me a date when the Constitution changes?”

They went back and forth like this a while longer, and then Chief Justice Roberts, followed by Justice Kennedy, took the conversation elsewhere. Read the full transcript of today's oral arguments here.