WASHINGTON (CNS)—The federal Defense of Marriage Act, or DOMA, defining marriage as between one man and one woman, is unconstitutional under the Equal Protection Clause, the Supreme Court ruled June 26 in a 5-4 opinion.

In a separate case, the court sent back to lower courts a challenge to California’s Proposition 8, the voter-approved initiative barring same-sex marriage. The apparent result is that same-sex marriage will again be legal in California as soon as the 9th U.S. Circuit Court of Appeals formally dismisses the case, as the high court instructed it.

In this second 5-4 ruling, with a different lineup of justices, the court remanded the case on the grounds that the individuals who defended the law in court lacked legal standing to do so.

Neither decision will have the effect of requiring states to honor same-sex marriages from other jurisdictions, but the DOMA case likely will affect how the federal government must treat same-sex marriages for purposes ranging from Social Security benefits to taxation, immigration and benefits for military spouses.

The opinion by Justice Anthony Kennedy blasted the law as having “the avowed purpose and practical effect … to impose a disadvantage, a separate status, and so a stigma upon all who enter into same-sex marriages made lawful by the unquestioned authority of the states.

“The act’s demonstrated purpose is to ensure that if any state decides to recognize same-sex marriages, those unions will be treated as second-class marriages for purposes of federal law,” Kennedy wrote. “This raises a most serious question under the Constitution’s Fifth Amendment.”

Kennedy was joined in the ruling by Justices Stephen Breyer, Ruth Bader Ginsburg, Sonia Sotomayor and Elena Kagan. Chief Justice John Roberts wrote a dissent, arguing that the court should not have jurisdiction to rule in the case and that DOMA was constitutional. Justices Antonin Scalia and Samuel Alito also wrote dissents. Justice Clarence Thomas joined Alito’s dissent and Roberts joined part of Scalia’s.

The California case was brought by two couples who were denied marriage licenses after the state’s voters in 2008 approved a constitutional amendment limiting marriage to heterosexual couples. The law was passed after the state Supreme Court ruled earlier that year that statutes banning same-sex marriage were unconstitutional.

After a federal District Court found that Prop 8 served no legitimate purpose and violates due process and the equal protection rights of same-sex couples to marry, the 9th U.S. Circuit Court of Appeals upheld that conclusion, although on a narrower legal finding. While litigation proceeded, Prop 8’s ban on same-sex marriages was allowed to stand.

The state of California declined to defend Prop 8 when two couples sued to block it, so individuals who supported the law took up its defense.

In an opinion written by Roberts, the Supreme Court ruled that those individuals lacked the legal standing to defend the law in federal court. The effect of the decision appears to be that the California trial court’s ruling that Prop 8 is unconstitutional will stand, at least initially. That would allow same-sex marriages to resume in California.

California Gov. Jerry Brown directed his state Department of Public Health, which oversees marriage licenses, to tell local authorities to begin issuing them for same-sex couples as soon as the 9th Circuit lifts its temporary stay in place while the court case proceeded. It was unclear how long that might take, but California legal observers suggested it would be a matter of perhaps a few weeks.

In his opinion, Roberts wrote: “It is not enough that the party invoking the power of the court have a keen interest in the issue. That party must also have ‘standing,’ which requires, among other things, that it have suffered a concrete and particularized injury. Because we find that petitioners do not have standing, we have no authority to decide this case on the merits, and neither did the 9th Circuit.”

Roberts was joined in that ruling by Scalia, Breyer, Sotomayor and Kagan. Neither the opinion of the court nor the dissent by Kennedy addressed the issue of same-sex marriage. Both dealt only with whether the parties to the lawsuit had the right to bring the court case, challenging a law instituted through the voter initiative process.

The New York case over DOMA arose when Edith Windsor inherited the estate of Thea Spyer, her partner of more than 40 years. The two had married in Canada in 2007. Windsor was held liable for $363,000 in federal estate and income taxes, which would not have applied to her had her spouse been a man.

Under the 1996 DOMA, marriage is defined as between one man and one woman for federal government purposes such as Social Security benefits, federal programs, immigration and federal estate and income taxes. It also said no political jurisdiction is required to recognize a same-sex marriage from another jurisdiction. The June 26 ruling did not address that provision of the law.

Lower courts had upheld Windsor’s argument that the law is unconstitutional. DOMA had the support of the administrations of Presidents Bill Clinton and George W. Bush and at first of President Barack Obama. But in 2011, the Justice Department announced that the attorney general had determined that Section 3 is unconstitutional as applied to legally married same-sex spouses. The administration said federal agencies should continue to enforce the law, but that the government would no longer defend it in court.

The case to uphold DOMA was taken up by a group of members of Congress, known as the Bipartisan Legal Advisory Group of the U.S. House of Representatives.

The U.S. Conference of Catholic Bishops, other religious groups and various organizations opposed to same-sex marriage had urged the court to issue rulings that upheld the traditional definition of marriage.

In 29 states, constitutional amendments ban same-sex marriage, while 12 states and the District of Columbia recognize such marriages. Another eight states recognize civil unions or domestic partnerships, with some having overlapping bans on same-sex marriage. Hawaii gave the legislature power to ban same-sex marriage.