WASHINGTON — When the U.S. Supreme Court struck down part of the federal Defense of Marriage Act (DOMA) last June, legal scholars expected no further ruling from the justices on this issue for some years.

Yet now, in the wake of several lower-court decisions overturning state laws banning same-sex "marriage," as well as a growing federal push for "marriage equality," experts predict the high court may decide another landmark case by 2015.

"The court could hear another case — more likely, two or more appeals to court decisions in favor of same-sex ‘marriage’ — next term; and, thus, issue a decision by June 2015," Gerard Bradley, a professor at the University of Notre Dame Law School, told the Register.

Legal experts on both sides of the issue say that Justice Anthony Kennedy’s majority opinion in United States v. Windsor, which found that DOMA denied legally married same-sex couples equal protection under the law, paved the way for the latest round of lower-court decisions overturning state bans on same-sex "marriage," despite the fact that the high court had upheld the sovereignty of state laws governing marriage.

In Windsor, Justice Kennedy wrote that the federal law expressed an irrational and unlawful animus toward persons with same-sex attraction. "The Constitution’s guarantee of equality must at the very least mean that a bare congressional desire to harm a politically unpopular group cannot justify disparate treatment of that group," stated Kennedy.

Justice Antonin Scalia, in his stinging dissent to the majority opinion, warned that it would have far-reaching consequences for the nation’s marriage laws. "It takes real cheek for today’s majority to assure us, as it is going out the door, that a constitutional requirement to give formal recognition to same-sex marriage is not at issue here — when what has preceded that assurance is a lecture on how superior the majority’s moral judgment in favor of same-sex marriage is to the Congress’ hateful moral judgment against it," Scalia wrote at the time.

 Over the past few months, federal judges in Virginia, Oklahoma, Utah and Texas issued decisions that found state amendments defining marriage as the union of a man and a woman to be unconstitutional, while rulings in Kentucky and Ohio signaled that such laws may not survive for long.

"Government interests in perpetuating traditions, shielding state matters from federal interference and favoring one model of parenting over others must yield to this country’s cherished protections that ensure the exercise of the private choices of the individual citizen regarding love and family," stated Judge Arenda Wright Allen in her ruling that overturned Virginia’s amendment, though the federal judge also issued a stay pending an appeal.

Notre Dame’s Bradley acknowledged that he was "surprised at the speed with which lower federal courts have run with the ‘spirit of Windsor,’ ignoring its rule of decision in favor of state sovereignty" with regard to laws governing marriage.

In Windsor, the majority opinion stated: "The definition of marriage is the foundation of the state’s broader authority to regulate the subject of domestic relations. ... Consistent with this allocation of authority, the federal government, through our history, has deferred to state-law policy decisions with respect to domestic relations."

William Duncan, director of the Marriage Law Foundation based in Washington, told the Register that the recent spate of court rulings underscored the Supreme Court’s game-changing role in advancing the debate on sensitive cultural and social issues.

It is not yet clear which marriage cases moving through the courts are most likely to secure a review during the Supreme Court’s next term.

But the Obama administration’s strong advocacy for "marriage equality" has introduced a further complication to that calculus.

On Feb. 10, Eric Holder, the attorney general of the United States, announced additional regulations that would govern the Department of Justice’s policies for dealing with individuals who were legally married to same-sex spouses anywhere in the U.S. or abroad.

Department employees were directed to ensure "equal treatment for same-sex married couples" in prison visitation and court proceedings, among other settings, even if the state of residence did not recognize such marriages.

Holder’s policy change follows on the heels of new regulations governing the treatment of same-sex married couples at the Department of Defense, the Internal Revenue Service and the Departments of State and Education.

The regulations have placed additional pressure on states that oppose recognition of same-sex "marriage" in their marriage laws. And some experts see the administration’s aggressive policy as a tactic that will force states to retreat from their defense of traditional marriage.

A growing number of state attorneys general have refused to enforce state marriage laws barring same-sex couples.

During a Feb. 25 address before the National Association of Attorneys General, Eric Holder suggested such actions could be justified if constitutional principles were carefully applied.

"I believe we must be suspicious of legal classifications based solely on sexual orientation," said Holder.

 And in February, Indiana lawmakers failed to approve a proposed constitutional amendment that would effectively bar "marriage equality" in the state, and homosexual-rights activists marked the impasse as a win, though same-sex couples still can’t marry there.

But the same language had easily passed the last time it was introduced, and so the failure to secure the second step in a required two-step process appeared to reveal a growing unease among GOP lawmakers.

For now, those who want to halt the Obama administration’s campaign for marriage equality have turned to Congress, endorsing the proposed State Defense of Marriage Act.

"Under President Obama, the federal government has tried to redefine marriage and to undermine the constitutional authority of each state to define marriage consistent with the values of its citizens. The Obama administration should not be trying to force gay marriage on all 50 states," said Sen. Ted Cruz, R-Texas, who introduced the bill with Sen. Mike Lee, R-Utah.

The U.S. Conference of Catholic Bishops has endorsed both the State Defense of Marriage Act and the proposed federal Marriage Protection Amendment (H. J. Res. 51), introduced by Rep. Tim Huelskamp, R-Kan.

In a Feb. 19 letter to Huelskamp, Archbishop Salvatore Cordileone of San Francisco, the U.S. bishops’ point man on marriage, said the proposed "amendment would secure in law throughout the country the basic truth known to reason that marriage is the union of one man and one woman."

However, as Capitol Hill prepares for another decision by the high court on marriage, it will be tough for Huelskamp, Cruz and other sponsors of the proposed legislation to marshal adequate support.

A longer version of this story ran on NCRegister.com.