(Editor’s note: This article was originally published at thenation.com and is re-posted here with permission. The U.S. Supreme Court will conduct oral hearings on California's Proposition 8 on March 26 and on the Defense of Marriage Act, or DOMA, on March 28.)

In case you haven’t noticed, the biggest question facing the Supreme Court when it decides the gay marriage cases this spring has become whether it can rise to the level of LGBT rights ferocity already achieved by American business leaders, moderate Republicans and the Obama administration. By the end of last week, when all the amicus briefs in support of striking down California’s Prop 8 and the Defense of Marriage Act (DOMA) had been filed, support for marriage equality seemed to have been transformed into the new normal — at least outside the confines of the Court.

In fact, judging from the press coverage of the briefs, if the justices don’t rule in favor of gay marriage, it is the Court that will look bad. This perception is an incredible achievement, a brilliant exercise in political framing by the lawyers and legal organizations behind the two cases, who mobilized the amicus show of force. The business brief and the Republican brief, especially, are clearly designed to provide political cover for the Court’s five conservative Justices.

While nothing is certain, there is virtually unanimous agreement among lawyers and law professors that the tougher case for gay rights groups is the challenge to Prop 8 rather than the one to DOMA. The Prop 8 case raises the question of whether all of the forty other state laws banning gay marriage are constitutional, while DOMA implicates only a federal recognition policy that leaves variance in state laws intact.

The best hope for winning Hollingsworth v. Perry, the Prop 8 case, remains either securing a narrow ruling that invalidates only the California law, or persuading the Court that it need not reach the merits at all, relying on the argument that those defending Prop 8 lack the necessary standing because they are private parties that have no authority to enforce it. (The governor and attorney general of California declined to defend the law.) From the beginning, though, the Ted Olson-David Boies strange bedfellows team that brought the case has argued that every law banning gay marriage should be struck down. Even six months ago, that position seemed too radical to attract much support outside the circle of true believers.

Now, however, a ruling of national scope is precisely the outcome endorsed in the brief filed by 100 corporations and in the Republican brief signed by luminaries including former White House officials Ken Duberstein (Reagan Chief of Staff) and Stephen Hadley (Bush National Security Advisor); Iraq War hawk Paul Wolfowitz; two Chairs of the Council of Economic Advisers under Bush; the former Director of the Congressional Budget Office; a Justice Department official from the Nixon Administration; the former Chair of the Federal Communications Commission, who is also Colin Powell’s son; and four former Republican governors. And, oh yes, Clint Eastwood.

What happened to make possible this conservative blessing of what had seemed to many like such a radical outcome? Fundamentally, the only change is that the political gestalt has shifted so that what was always a conservative claim — to gain access to the core institution for privatizing a broad range of social functions — is increasingly being endorsed by conservatives. Sooner or later, it had to happen.

Nonetheless, it is unquestionably true that the conventional understanding of where the center of American politics stands on this issue has dramatically moved. The reasons are many. A cumulative process, especially since 2009, has driven support for legalizing gay marriage ever higher in public opinion polls. The shock of the 2008 defeat in California catalyzed a younger generation of gay men and lesbians, with ardent support from straight allies, to insist on marriage as the premier gay rights issue. Since that election, gay groups have won a series of state-level battles, as several legislatures legalized equal marriage, including New York (with one chamber controlled by Republicans). At the national level, Congress repealed Don’t Ask Don’t Tell.

The icing on the wedding cake came with last November’s election. Voters in three states affirmatively chose to adopt gay marriage, and Minnesota voters rejected the attempt to pass a Prop 8-like measure. Moreover, the first President ever to endorse marriage equality was handily re-elected, without his position ever surfacing as a controversial issue in the campaign. Indeed, support for gay marriage, along with immigration reform, has become the litmus test most frequently identified in the press for assessing whether the Republican Party can rebrand itself as moderate and escape terminal fuddy-duddyism.

Of course, the outcome in the Supreme Court will be decided not by polls or pundits but by nine individuals; actually by six, since there is no question as to which result Justices Scalia, Thomas and Alito will endorse. But Justice Kennedy, who wrote the two strongest opinions supporting gay equality in past cases, and even Chief Justice Roberts, who has no real track record in this area, are likely to take seriously the libertarian and business arguments for allowing gay couples to marry. Not doing so would continue the house-divided status quo, in which one’s marital status and even the possibility of divorce depends on an increasingly irrational mélange of different state laws. And, as the firepower across the political spectrum in support of gay marriage so dramatically demonstrates, the ultimate resolution is inevitable. Best just to bite the bullet and do it now.

If this all sounds a bit too good to be true, maybe it is. Justice Kennedy is also a strong believer in state sovereignty, and a decision forcing legal change in forty-one states may be too much for him to join. The great bulk of the US population lives in a jurisdiction where gay marriage is not legal. The defenders of Prop 8 will to try assuage the justices that if the political process is left to work, more and more states will re-amend their constitutions and change their statutes to gradually adopt gay marriage laws on their own, without judicial “interference.” In addition, the liberal justices who support gay marriage may worry that a sweeping Roe v. Wade-like decision will trigger a massive backlash. These considerations combine to make that standing argument sure seem like a nice way to kick a vexatious can down the road.

This is the new political environment in which the legal arguments about marriage equality will succeed or fail. But that might not be enough to put gay marriage supporters over the top. Supreme Court justices breathe the same cultural air that the rest of us do, but they don’t have the luxury that politicians have to just say — hey, guess what, I’ve changed my mind on that one. The substantive legal arguments have to be both persuasive and consistent with other applications of the same body of doctrine. Even if a judge wants to see a certain result, the opinion “has to write” — the analytic structure has to support that result.

The substantive questions in the DOMA case (which also has a jurisdiction/standing question, though it is probably less likely to prove decisive than the one in Perry) all arise from the Equal Protection Clause of the Fourteenth Amendment. In previous civil rights cases, the Court has developed a set of increasingly stringent levels for reviewing legislative classifications, with racial classifications receiving the highest level, or strict scrutiny; and gender classifications requiring heightened scrutiny, which is somewhat less rigorous. The baseline and point of comparison for both is called rational basis review, a lenient standard under which courts defer to legislative judgment if the distinction drawn has a rational relationship to any legitimate government interest.

So far, the Court has not explicitly applied either heightened or strict scrutiny to sexual orientation discrimination, but it did nonetheless strike down an anti-gay state law by applying what seemed to be a heightened version of rational basis review. As a result of the Supreme Court not being more transparent in its approach in gay cases, the lower federal courts are all over the board in terms of whether they apply heightened scrutiny, rational basis review with bite, or deferential rational basis review.

The selection of the standard is critically important because it usually determines the outcome as to whether a law is ruled unconstitutional. For example, the Justice Department argues in its brief that DOMA is unconstitutional if heightened scrutiny is applied, but valid if rational basis review is used, unless the Court uses heightened rational basis, in which case DOMA is unconstitutional after all. (Are you still with me?) The most important outcome of the DOMA case for the future of gay rights law is that the Court is likely to declare itself on which standard should be applied to any law that discriminates based on sexual orientation.

It is also true in Perry, the Prop 8 case, that the Court could determine the law’s constitutionality by using an Equal Protection analysis. However, in that case there is another doctrinal option. Under the Due Process Clause (i.e., no state can deprive an individual of liberty without due process of law), the Court has held repeatedly that the right to marry is a fundamental right. When a law deprives persons of a fundamental liberty right, the denial must be narrowly tailored to achieve a compelling state interest.

Until just a few years ago, the majority of courts deciding gay marriage cases ruled that although there was a right to marry, there was not a right to same-sex marriage. Those two examples, judge after judge said, were just different, essentially and tautologically so. But U.S. District Court Judge Vaughn Walker, who conducted the trial in the Prop 8 case, ruled that one basis for the law’s unconstitutionality is its violation of the due process liberty right to marry.

The Olson-Boies brief in the Supreme Court opens with this liberty claim; the equal protection argument comes second. Usually litigators begin a brief with what they believe is their strongest argument, suggesting that Olson may push the Court for a victory based on recognition that the marriage-childbearing link being pressed by Prop 8’s defenders doesn’t justify denial of a right as important as marriage. Indeed, the first sentence in the brief quotes from a 1978 Supreme Court decision stating that marriage is “the most important relation in life,” a quotation repeated twice more in the first four pages of the brief.

If Perry is decided on liberty grounds, its scope will be limited to marriage rather than applying to all sexual orientation classifications. But for many people, that would be like saying that a truce applies only to ending a war, rather than preventing all future battles. If gay couples can’t be excluded from marriage, what forms of government discrimination could possibly be constitutional?

The next stage in this saga is that the Court will hear oral arguments in Perry on March 26 and in Windsor v. United States, the DOMA case, on March 27, in what will be a feast for constitutional law buffs. Based on the questions asked by the justices, the betting is certain to be fast and furious on how the cases will come out. That enterprise, however, is notoriously prone to mistakes, given how often the questions reflect a Justice playing devil’s advocate rather than tipping her hand.

Because these cases will be among the last argued during the current term, they will likely be among the last in which the opinions are issued. There is no deadline for when the Court must decide cases, but it will announce all of the term’s opinions before leaving for the summer. For gay marriage, that almost certainly portends nuptials — or not — in June.

About Nan Hunter

Nan Hunter is Professor of Law at Georgetown University Law Center and Associate Dean for Graduate Programs. She also consults with the Williams Institute at UCLA as its Legal Scholarship Director. She co-authored the law school casebook “Sexuality, Gender and the Law,” now in its third edition, and has published dozens of law review articles in both sexuality and gender law and health law. During the Clinton Administration, she served as Deputy General Counsel at the U.S. Department of Health and Human Services. Her awards include the Pioneer of Courage award from the American Foundation for AIDS Research and the first Dan Bradley award from the National LGBT Bar Association. She blogs at www.hunterofjustice.com and www.thenation.com.