With the Supreme Court only days away from major rulings on same-sex marriage, President Obama faces the prospect of having to make his own difficult decisions about the definition of wedlock.

Gay rights advocates are already pressing Obama to immediately broaden the federal government’s recognition of legally married same-sex couples if the court strikes down a ban on providing federal benefits to them.

The question for Obama turns on whether the federal government should extend full benefits to gay couples living in states that don’t recognize their marriages.

Obama would face rare, concrete decisions on the politically combustible question of same-sex marriage — an area he has largely left to the purview of courts and state legislatures.

Advocates have pressed the issue of benefits with White House aides in recent months, according to people familiar with the discussions. The advocates have pushed for a uniform standard that would make the most benefits available to legally married couples across the board. Officials have not signaled what Obama would do.

Same-sex marriage status in the U.S., state-by-state

“Equal protection means that every family should have access to the same protections they need regardless of state borders,” said Fred Sainz, a spokesman for the Human Rights Campaign, a leading gay rights advocacy group. “We’ll fight to make sure that all legally married gay couples can access the greatest number of federal benefits and protections.”

The Supreme Court could issue rulings as early as Monday on two significant marriage cases. One is expected to decide the fate of California’s voter-approved ban on same-sex marriage, which was overturned by lower courts.

Obama’s choices on federal benefits arise from the other case, in which the justices are expected to determine the constitutionality of a key provision of the 1996 Defense of Marriage Act that prohibited the federal government from making benefits available to same-sex couples.

The Obama administration filed a brief in that case arguing that the law was unconstitutional. The measure’s defense was championed by House Republicans, who hired Paul Clement, solicitor general under President George W. Bush, to argue that the bipartisan majorities in Congress that approved the law had the right to protect heterosexual marriage no matter what a handful of states might decide.

Obama’s potential dilemma stems from the fact that eligibility for some federal benefits — including Social Security payments to spouses and marital tax deductions — is determined based on the marriage laws of the states where the couples live and not where they were wed.

If the Supreme Court overturns the Defense of Marriage Act, full benefits would be available to same-sex couples who marry and live in the dozen states that legally recognize their relationships. But legally married gay couples that live in states that don’t recognize their marriages would be ineligible for a range of federal benefits.

Advocates say Obama could eliminate the discrepancy with an executive order or new regulations setting a couple’s “place of celebration” as the deciding factor in whether the U.S. government recognizes a marriage for the purposes of providing benefits.

Any move by Obama to broaden the effect of the court’s ruling could risk sparking new legal battles over the issue in the more than two dozen states that have moved to prohibit same-sex marriage, according to conservative activists.

Only one section of the law is under challenge, and it might yet be upheld. Another section states that no state “shall be required to give effect to any public act, record, or judicial proceeding” of any other state “respecting a relationship between persons of the same sex that is treated as a marriage.”

Gary Bauer, president of American Values, an evangelical group, said making federal benefits available to gay couples no matter where they live would be an “overreach” that would be “countered by lawsuits and every other tool available to the people of those states.”

“Whatever authority [Obama] has in this regard, I don’t think it extends to something as fundamental as a de facto redefinition of marriage in states who through their democratic processes have made it clear they oppose such a change,” Bauer said.

If the Supreme Court upholds the law, Obama would have to continue enforcing restrictions he considers unconstitutional while figuring out how to respond to what many of his core supporters would see as a major setback to the gay rights movement. Many of them would expect him to push Congress to repeal the law.

As president, Obama has largely sidestepped the marriage issue. He endorsed same-sex marriage rights in the midst of his reelection campaign, spurring a flood of campaign cash from gay donors, and his administration joined in the effort to overturn the benefits provision of the Defense of Marriage Act. But Obama has said the question of legalized marriage should be left to the states.

“There will be tremendous pressure on the White House and on the president personally to move very quickly to implement the judgement and to implement it broadly,” said Richard Socarides, a longtime gay rights activist who was an adviser in the Bill Clinton White House.

“Thirty days is what he’s got,” Socarides added. “These are real people suffering real injury. If anybody tries to argue that they need six months or a year, there are going to be riots in the streets.”

White House officials declined to discuss the matter in detail, saying it would be premature to speculate about a future ruling. Still, spokesman Shin Inouye said, “The administration will, of course, be prepared to address any implications of the court’s decision.”

The implications could be challenging.

According to research prepared by the Human Rights Campaign, federal agencies use an array of definitions of marriage to determine eligibility.

Some benefits would become available to married gay couples no matter where they live because agencies in certain cases make the determination based on where the wedding took place. That is the case for immigration issues and veterans benefits.

But, according to the rights group, a number of major benefits could be denied gay couples in states without legal marriage — including the right to take leave from work to care for a spouse or to file federal income taxes jointly.

The issue has gained attention among advocates in recent weeks as anticipation builds about what many hope will be a landmark ruling. A number of gay rights advocates were reluctant to discuss the implications for Obama, however, wary of appearing to nudge the court in a particular direction.

Advocates said Obama’s response to the court’s actions — no matter what the court decides — will be closely watched.

Many advocates have seen him as a reluctant champion, pushed to support gay rights from the start of his presidency. Activists were outraged when Obama’s administration, in his first term, initially filed court arguments standing up for the Defense of Marriage Act. But they widely hailed him when he reversed the stance.

His record also includes the repeal of the military’s “don’t ask, don’t tell” policy on openly gay service members.

Obama cited his record during remarks Thursday night at the White House as part of a Pride Month reception for lesbian, gay, bisexual and transgender activists. He used the reception to present himself as an advocate for expanding marriage rights. “I’ll continue to support marriage equality and states’ attempts to legalize it,” he said.