By Bill Mears CNN Supreme Court Producer
(CNN) - There are no hints and trying to predict an outcome is a slippery slope. But for those anxiously awaiting a Supreme Court decision on same-sex marriage - arguably its biggest issue this term - knowing potential scenarios is key.
Familiarity with legal terminology, like "DIG" or "standing" also can help prepare both sides to gauge expectations - thinking really big or really small - when rulings on two cases are issued this month.
This is especially true in the petition from California over a voter-approved ban on gays and lesbians marrying.
"The court has several ways to decide this case - from a very broad, sweeping conclusion with respect to the rights of our citizens in this country, to a narrower ruling that would be limited basically to California," attorney Theodore Olson told CNN.
He argued on behalf of homosexual couples before the high court in March.
The justices are working separately in their chambers, trying to forge opinions on same-sex marriage and more than two dozen other cases.
Ten states now allow gays and lesbians to legally wed: Connecticut, Iowa, Maine, Maryland, Massachusetts, New Hampshire, New York, Rhode Island, Vermont, and Washington, as well as the District of Columbia. Delaware and Minnesota's recently passed laws take effect this summer.
'DIG' or 'standing'
It is estimated about 120,000 legally married homosexual couples live in the United States.
There is division within the ranks of both sides about whether the high court will or even should issue a sea-change ruling on the constitutional "equal protection" question.
Some activists and politicians - even some justices - think the elected branches may be in a better position to drive the same-sex marriage issue, not the courts.
"For those hoping the Supreme Court will say there is a broad right for same-sex couples to be married, they're likely to be disappointed," said Thomas Goldstein, SCOTUSblog.com publisher and a Washington lawyer.
"In the end, probably the wording of the decision will give more momentum to those states that are recognizing those rights but it won't force them to do so."
Two marriage cases are before the court:
One involves an appeal of the Defense of Marriage Act, which was approved by Congress in 1996 and defines marriage as that between a man and a women. It says in part that legally married same-sex couples cannot enjoy the range of financial and other benefits enjoyed by heterosexual married couples.
Edie Windsor, an 84-year-old New York woman, is the key plaintiff. She was forced to pay extra estate taxes when her longtime spouse, Thea Spyer, died.
The second involves the California ban or Proposition 8.
The court has set itself up to "punt" on both Proposition 8 and defense of marriage, avoiding for now consideration of the constitutional questions.
This legal letdown could turn on "standing," or the legal authority or eligibility to make the case.
California's governor has refused to defend Proposition 8 in court, leaving a coalition of private groups to step in before the courts.
Can they establish a legitimate "harm" to satisfy court scrutiny?
The justices could also "DIG" it - or have the case "dismissed as improvidently granted." Basically, the justices would be saying they should not have taken the appeal in the first place.
"If the issue is letting the states experiment and letting the society have more time to figure out its direction, why is taking a case now the answer?" Justice Sonia Sotomayor asked at March oral arguments.
Some of her conservative colleagues seemed to agree as well.
Whether on standing or "DIG" grounds, the differences are important.
"'Digging" would likely mean lower court rulings striking down Proposition 8 would hold, allowing California gay and lesbian couples to marry if they choose. How quickly that would happen is unclear if further legal challenges are filed.
But a "standing" ruling would likely nullify everything, perhaps forcing both sides to start all over again in the lower courts, and limiting the reach of gay marriage to perhaps only a few California counties.
Multiple options for ruling
Another likely statewide referendum next year could preempt the legal battles and finally settle the matter, at least in that state.
Recent polls show growing support for same-sex marriage in California, a trend reflected nationwide.
So, the court really has four options to rule on Proposition 8 and same-sex marriage supporters believe in each scenario, they would win.
Lawyers for the two couples at the center of the fight are cautiously optimistic, with the emphasis on "cautiously."
"Trying to read too much into to those questions is a risky proposition," attorney David Boies told CNN. "The court is exploring all four of these options."
But backers of Proposition 8 think the court will want to stay of the political fight, and allow the measure to stand, at least for now.
"A victory for us means to issue returns to the people, to the legislatures, and to the elected representatives - where this debate belongs," said Charles Cooper, the lawyer who argued at the Supreme Court for Proposition 8.
The federal law, DOMA, has its own sticky procedural questions.
President Barack Obama now believes the federal law is unconstitutional, and has refused to defend it in court.
Traditionally that role would fall to the solicitor general's office. That executive refusal raised the question of whether any party could now rightfully step in and defend the law - the idea being in any such fight you need opposing sides with a valid stake in the outcome.
Congressional Republicans, operating officially as the Bipartisan Legal Advisory Group of the U.S. House of Representatives, took over the role normally filled by the Justice Department.
"Without the House's participation," said attorney Paul Clement, representing House leaders, "it is hard to see how there is any case or controversy here at all. Both Ms. Windsor and the executive [branch] agree that DOMA is unconstitutional and that Ms. Windsor was entitled to a [tax] refund. And the lower courts granted them all the relief they requested. Only the House's intervention provides the adverseness that Article III [federal court jurisdiction] demands."
War of words
The court could dismiss that case on standing grounds, but most legal analysts see a more substantive ruling on the merits.
Confusing enough? Legal experts, government and private lawyers, and the blogosphere have been waging a war of words in recent months, expressing varying amounts of certainty of what the court will do when deciding those questions.
But inside the court, there are no hints. It is familiar refrain among its nine members over the Washington parlor game of guessing the outcomes: "At the Supreme Court, those who know, don't talk. And those who talk, don't know."
