Scottsdale, Ariz. — Alan Sears, who has run the Christian legal group Alliance Defending Freedom since its founding 20 years ago, turned to a picture of Abraham Lincoln in his office here and noted the decades of blood and tears it took to abolish slavery.
“I think there is no question that one day, this country will again recognize that marriage is between a man and a woman,” said Mr. Sears, a former top official in the Reagan Justice Department.
The comparison may or may not prove apt, but these are heady days for Alliance Defending Freedom, which, with its $40 million annual budget, 40-plus staff lawyers and hundreds of affiliated lawyers, has emerged as the largest legal force of the religious right, arguing hundreds of pro bono cases across the country. It has helped shift the emphasis of religious freedom enshrined in the Constitution. For decades, courts leaned toward keeping religion out of public spaces. Today, thanks to cases won by the alliance and other legal teams focused on Christian causes, the momentum has tilted toward allowing religious practices with fewer restrictions.
The group last Monday celebrated a major victory in the Supreme Court, where a client, the Town of Greece, N.Y., won the right to open council meetings with mainly Christian prayers.
The alliance awaits the decision in another case that could redefine the boundaries of religious freedom — the challenge by its client Conestoga Wood Specialties, along with Hobby Lobby, to the provision in the Affordable Care Act requiring companies to cover birth control in employee-funded health plans.
Things have gone less well in the fight against same-sex marriage, but the group is in the fray, arguing before the United States Court of Appeals for the Fourth Circuit in Richmond, Va., on Tuesday in defense of Virginia’s marriage restrictions. This case, like that of Oklahoma, which the group also argued in a federal appeals court, may end up in a climactic Supreme Court battle in the year ahead.
Alliance Defending Freedom was created by Christian leaders including Bill Bright, the founder of Campus Crusade for Christ, and James C. Dobson Jr., the founder of Focus on the Family. In the early 1990s the groups had watched with growing dismay as secular groups like the American Civil Liberties Union used the courts to ban school prayer and advance abortion rights even as an emerging gay-rights movement threatened, in their view, to upend the country’s social values.
“People of faith were being outgunned in court,” said Mr. Sears, 62, a Roman Catholic in an organization populated with evangelical Protestants. So the group — then called the Alliance Defense Fund — was founded to foster Christian legal firepower.
The new Christian lawyers have proved to be sophisticated litigants in court, wielding constitutional arguments without invoking religion. But outside the courtroom, the group has provoked the enmity of gay-rights advocates, in particular, by expressing harsh views such as those in a book Mr. Sears co-wrote in 2003, “The Homosexual Agenda: Exposing the Principal Threat to Religious Freedom Today.” It describes gay people as “trapped” and gay-rights advocates as bent on creating a nation of “broken families and broken lives.”
One lesson Christian conservatives learned, Mr. Sears said, is that lower court decisions that violate what he considers to be original constitutional principles can lead to more dangerous assaults. Griswold v. Connecticut, for example, the 1965 Supreme Court ruling that Connecticut could not ban the use of contraceptives by married couples, was a travesty, he said, because it established a new right of privacy, used in 1973 to justify legalizing abortion in Roe v. Wade.
In 2003, the alliance worked against what became another landmark ruling in Lawrence v. Texas, which declared laws against “homosexual sodomy” unconstitutional. Its lawyers feared that the decision would help open a legal path to same-sex marriage.
The group originally focused on channeling donations to other lawyers as well as training more Christian lawyers in issue-oriented litigation, which remains a major part of its work. Its summer fellowship program has drawn 1,300 law students, and some 1,700 practicing lawyers have attended training sessions.
But the alliance soon expanded its own legal team, joining a cluster of like-minded, nonprofit law firms including Liberty Institute, which is devoted entirely to “religious liberty” issues; the American Center for Law and Justice; the Becket Fund for Religious Liberty; Liberty Counsel; and the Pacific Justice Institute. Alliance Defending Freedom, which changed its name in 2012, relies on private donors, whom it does not disclose.
“A.D.F. and the other groups wanted to counter more liberal legal forces, and they have largely achieved that goal,” said Douglas Laycock, an expert on law and religion at the University of Virginia Law School. “On the whole, they work at pretty high levels, and they’ve got a lot of boots on the ground.”
Along the way, the alliance has sometimes ruffled the feathers of sister organizations. When California state officials declined to defend Proposition 8, the amendment banning same-sex marriage, the alliance took up the cudgel. But when it lost in federal court in 2010 in the case, Hollingsworth v. Perry, Liberty Counsel complained publicly that Alliance Defending Freedom had excluded it and had performed poorly.
Many of the alliance’s legal victories (it says it has an 80 percent success rate) have involved defense of religious activities and symbols at universities and in public spaces.
But the alliance has gained a reputation as a hard-line opponent of gay rights, and critics say the principles in its legal briefs mask prejudice, a contention that Mr. Sears denies.
Fred Sainz, a vice president of the Human Rights Campaign, a gay-rights group, said, “They are easily the most active antigay legal group.”
On same-sex marriage, the group did secure a temporary win in California in 2004 when it forced Mayor Gavin Newsom of San Francisco to stop granting same-sex marriage licenses. But more recently, this group, like others seeking to preserve marriage restrictions, has suffered a chain of defeats.
Beyond its lawsuits and training of legal allies, the alliance is often involved behind the scenes, helping state officials prepare briefs justifying marriage restrictions or, in an example uncovered by RH Reality Check, a reproductive-rights website, mobilizing states to sign friend-of-the-court briefs in the contraceptive-mandate case.
The legal group has a growing international program, working primarily in Europe, where it has helped defend religious displays before the European Court of Human Rights and Ireland’s ban on abortion.
In perhaps its most aggressive effort, the alliance organizes an annual Pulpit Freedom Sunday, enlisting pastors, who under federal rules may not endorse politicians or bills, to link “biblical principles” to politics in their sermons. In June, more than 1,000 pastors signed up to preach “the truth about marriage.”
Asked to evaluate the success of the Christian legal movement Mr. Sears said, “We’re much better off in terms of our ability to respond in court, but we’re still a long way from catching up with the other side. The A.C.L.U. had a 74-year head start and set a lot of precedents. Who knows what would have been the outcome if there had been more faith-based lawyers all along?”