President Obama supports same-sex marriage, that much we know. But we may soon find out just how much he supports it.

To explain: last May, Obama gave an interview to ABC’s Robin Roberts in which he said, “I think same-sex couples should be able to get married.” Last month, the President told legislators in his home state of Illinois that they should vote to legalize same-sex marriage. (The issue is stalled there at the moment.)

So it’s clear that President Obama believes that states should grant gay people the right to marry. The question, though, is whether he and his Administration believe that gay people have the constitutional right to marry, whether or not state legislators grant it to them. We should know the answer by the end of the month.

On March 26th and 27th, the Supreme Court will hear arguments on two cases relating to same-sex marriage. In the first, the Justices will weigh the constitutionality of the Defense of Marriage Act, or DOMA. That law, passed in 1996, forbids the federal government from recognizing same-sex marriages even in states where those marriages are legal. In the case before the court, Windsor v. United States, the Internal Revenue Service taxed the estate of a surviving same-sex spouse as if she were a stranger to the deceased. Since 2011, the Obama Administration has been on record as considering DOMA unconstitutional; it will not defend the law before the Justices.

The second case, Hollingsworth v. Perry, raises the broader question of whether gay people enjoy a constitutional right to marry. In that case, a district court in San Francisco ruled that Proposition 8, the California voter initiative that banned same-sex marriage, violates the Fourteenth Amendment guarantee of equal protection of the laws. The Obama Administration has not yet taken a position in the Proposition 8 case, though Justice Department sources indicate that the government may yet file a friend-of-the-court brief. In that brief, if it’s filed, we’ll learn what the Administration thinks about a constitutional right to marry. (The brief itself will be filed by Donald Verrilli, Jr., the solicitor general, but my sources say the decision on what it will argue will either be made by Attorney General Eric Holder or by the President himself.)

The issue has major legal and political implications. DOMA applies only in the nine states (and the District of Columbia) that already allow same-sex marriage. In virtually all of those states, same-sex marriage is politically popular, so siding with its supporters poses little risk for the President. The Prop. 8 suit is a very different matter. In that case, Obama could take the position, as the plaintiffs have, that the Constitution compels every state in the union to allow same-sex marriage. If adopted, this argument would turn the Hollingsworth case into the gay-rights equivalent of Loving v. Virginia, the 1967 landmark decision that said states could no longer ban interracial marriage.

Obama has generally been outspoken in support of gay rights—he led the abolition of Don’t Ask, Don’t Tell in the military during his first term—but he has been cautious on the subject of same-sex marriage. Many leading Democrats, including Vice-President Biden, announced their support for same-sex marriage before Obama did. The cautious move would be to duck the Hollingsworth case altogether. There are several ways the Supreme Court could resolve the case without having to consider the question of whether there is a constitutional right, in every state, to same-sex marriage. The Justices could rule that the plaintiffs in the case lack the standing to bring it at all. Likewise, the Court could affirm the Ninth Circuit’s judgment that it was unconstitutional for California to withdraw the right to same-sex marriage after granting it. Urging either of these limited rulings would allow the Justice Department to support the plaintiffs in the case without risking a political backlash in the states that still prohibit same-sex marriage.

But there is a problem with the cautious approach. In deciding not to defend DOMA, Holder wrote, “the president has concluded that given a number of factors, including a documented history of discrimination, classifications based on sexual orientation should be subject to a more heightened standard of scrutiny. The president has also concluded that Section 3 of DOMA, as applied to legally married same-sex couples, fails to meet that standard and is therefore unconstitutional.” Once the Administration—or the Supreme Court—concludes that one form of discrimination against gays is unconstitutional, it becomes more difficult to defend any form of discrimination. If there is no justification for the federal government to discriminate against gay people in DOMA, what justification is there when states do the same thing? Perhaps there is none—which argues for the broader prohibition on any kind of discrimination. The logic of the Administration’s DOMA position leads (if not quite inexorably) to the conclusion that all forms of discrimination against L.G.B.T. people must fall.

Supreme Court cases, especially high-profile ones, are rarely decided on the basis of such logical inferences. The Justices are as aware of the politics of same-sex marriage as the President is. Even those Justices who believe that the Constitution guarantees marriage equality may vote to proceed cautiously, in a state-by-state, step-by-step manner. But what’s become ever clearer is that the edifice of discrimination against gay people is falling. Maybe the President does not want to lead—and maybe the Supreme Court doesn’t want to, either—but the destination of the country on gay rights is clearer every day.

Photograph by Chip Somodevilla/Getty.