NEW YORK — For foes of same-sex marriage, their losing streak keeps growing. Some sense a lost cause, others vow to fight on.
On Election Day in 2012, they went 0-for-4 on state ballot measures. A year ago, the Supreme Court ruled that the federal government must recognize same-sex marriages. And during the past seven months, more than a dozen federal and state judges have struck down part or all of state-level bans on gay marriage, with no rulings going the other way.
Faced with these developments, some longtime opponents of gay marriage now say that its nationwide legalization via a Supreme Court ruling is inevitable. Others refuse to concede, and some leaders of that cohort will rally Thursday at a March for Marriage in Washington that they hope will draw many thousands.
The event’s main sponsor is the National Organization for Marriage, which engaged in several successful state campaigns against gay marriage before the 2012 votes in Maine, Maryland, Minnesota, and Washington state that reversed the tide.
The National Organization for Marriage is promoting the march with a website that evokes a ‘‘road to victory’’ and a video featuring dramatic background music.
‘‘A competition is won by those who take the field, not by those who sit on the sidelines,’’ the group’s president, Brian Brown, tells his supporters. ‘‘Friends, we need to take the field for marriage — and fight to win.’’
Brown, in a phone interview, said his best-case scenario hinged on a future ruling by the Supreme Court upholding the right of states to set their own marriage laws, rather than imposing same-sex marriage nationwide. Such a ruling would strengthen the position of the 31 states that currently ban gay marriage and might encourage grass-roots efforts in some of the other states to reimpose bans, Brown said.
‘‘We’d put this back in the hands of the democratic process,’’ Brown said. ‘‘We would have the people deciding for themselves.’’
If the Supreme Court ruled the other way, legalizing gay marriage nationwide, ‘‘We won’t go away,’’ Brown said.
He envisioned a resistance campaign comparable to that waged by the antiabortion movement since the Supreme Court’s 1973 Roe v. Wade decision established a nationwide right to abortion.
‘‘In the next year or so, we’ll either have a massive victory at the Supreme Court, or we’ll need to fight for 10, 20 years to undo the damage that the court has done,’’ Brown said.
In Congress, conservative Republicans have introduced two bills opposing same-sex marriage, but neither has drawn strong support even within GOP ranks. One would require the federal government to defer to state marriage laws, including those banning gay marriage; the other would amend the Constitution to limit marriage to the union of one man and one woman.
Among the scheduled speakers at Thursday’s march is Austin Nimocks, senior counsel with Alliance Defending Freedom, a Christian legal group that has fought in court on behalf of laws banning gay marriage.
He argues America would be better off if the Supreme Court allowed the current split among the states to continue, along with the public debate on the repercussions of gay marriage. ‘‘America has not fallen apart because some states have same-sex marriage and others do not,’’ he said. ‘‘We’ve been managing that for 10 years.’’
While Nimocks and Brown are optimistic that the Supreme Court will not impose same-sex marriage, other veterans of the fight against it think differently.
‘‘Let’s face it: Anybody who does not believe that gay marriage is going to be the law of the land just hasn’t been observing what’s going on,’’ Senator Orrin Hatch, a conservative Republican from Utah, told a radio interviewer last month.
Maggie Gallagher, a former president of the National Organization for Marriage, also expects that outcome. In a recent blog post, she said gay-marriage opponents needed to regroup and recognize that they have become ‘‘a subculture facing a dominant culture.’’
‘‘The way you keep a movement going is to define achievable victories,’’ she said in an interview. ‘‘The marriage movement is in the process of trying to figure out what that is.’’
A leading advocate of same-sex marriage, Evan Wolfson of Freedom to Marry, said his adversaries have been placed in an ever-weakening position by trends in public opinion polls and by the recent court rulings. One after another, the judges have said they heard no persuasive argument why gay couples should be denied the marriage rights afforded to opposite-sex couples.