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 U.S. Supreme Court ruled that the federal government must recognize same-sex marriages. And over 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 be rallying 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 prior to the 2012 votes in Maine, Maryland, Minnesota and Washington state that reversed the tide.

NOM 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,” NOM’s president, Brian Brown, exhorts his supporters. “Friends, we need to take the field for marriage — and fight to win.”

Brown, in a telephone 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 anti-abortion 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.

Among the scheduled speakers at the 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.

Nimocks argues that America would be better off if the Supreme Court allowed the current split among the states to continue, along with the public debate over 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 won’t 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,” Sen. Orrin Hatch, a seven-term 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 convincing argument why gay couples should be denied the marriage rights afforded to opposite-sex couples.

“All the defenses of discrimination conjured up by the dwindling hard-core of opponents have been exposed as indefensible, insufficient, or untrue,” said Wolfson.

In the political realm, Democrats increasingly see advocacy of gay marriage as a winning position, while the Republican Party — whose 2012 national platform opposes gay marriage — is now experiencing some divisions.

In several states, some GOP leaders have objected to planks in the state party platform that oppose same-sex marriage. Also, several of the GOP governors whose states are among those allowing gay marriage have accepted the new reality rather than continue railing against it.

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 U.S. Constitution to limit marriage to the union of one man and one woman.

Amid the string of defeats in court, many opponents of gay marriage have focused their wrath on the judges making those decisions.

Tim Wildmon, president of the American Family Association, depicted the rulings as “judicial tyranny.” Former Arkansas Gov. Mike Huckabee — who’ll be a featured speaker at Thursday’s march — called for the impeachment of the judge who struck down his state’s gay-marriage ban.

“When members of the judiciary act as if they were entitled to the power of all three branches of government, it creates a disturbing abuse of power,” Huckabee said in an email to The Associated Press.

Some conservative groups have launched fundraising appeals decrying recent cases where prominent people lost jobs or business opportunities because of their opposition to same-sex marriage. The Family Research Council, for example, depicted as “thuggery” the pressure that led to the resignation of Mozilla CEO Brendan Eich, who had supported a 2008 campaign against gay marriage in California.

“Our ability to express ourselves in the public sphere must never be repressed by the tyranny of political correctness,” wrote the council’s president, Tony Perkins, in a letter to supporters. “We must never submit to the radical leftist redefinition of human sexuality.”

Perkins’ group is a co-sponsor of Thursday’s march, as is the Coalition of African-American Pastors. The coalition’s leader, the Rev. Bill Owens, says he will intensify his advocacy work in black churches, seeking to make the case that same-sex marriage is not a civil rights issue.

Another co-sponsor is the Roman Catholic Archdiocese of Philadelphia, which is organizing a bus fleet to carry parishioners to the march.

One of the scheduled speakers is the Archbishop Salvatore Cordileone of San Francisco, who chairs the U.S. Conference of Catholic Bishops’ subcommittee on the promotion and defense of marriage.

A coalition of liberal politicians and gay-rights leaders in California has issued an open letter to Cordileone, urging him to skip the march. Many of the other scheduled speakers “have repeatedly denigrated lesbian, gay, bisexual and transgender people,” said the letter, suggesting the archbishop shouldn’t align with such viewpoints.

Along with the Catholic Church, several other major denominations remain adamant in opposing same-sex marriage.

“We stand strong on what the Scripture says about marriage between a man and a woman,” said the Rev. Ronnie Floyd after his recent election as new president of the Southern Baptist Convention.

A top Mormon leader reiterated opposition to gay marriage during the biannual general conference of the Church of Jesus Christ of Latter-day Saints in April.

“While many governments and well-meaning individuals have redefined marriage, the Lord has not,” said Neil Andersen.