SCOTTSDALE, Ariz. — A little more than a decade ago, the Alliance Defense Fund was a one-man operation.

Alan Sears worked in an executive suite, trying to build a public-interest legal firm to defend against what evangelical Christians saw as an attack on believers' values. Today, the organization headquartered in a nondescript office building in north Scottsdale has more than 100 employees and branch offices in six states; it files an average of one lawsuit a week — asserting itself in cases involving Christianity and schools, gay marriage and other social-conservative concerns.

"Our dreams were big and our desires were big, but we've been overwhelmed with the response," Sears said recently.

Since its founding in 1994, the Alliance Defense Fund has scored victories in cases involving funding and access for Christian student groups, school vouchers in Ohio, the Boy Scouts' policy of excluding openly homosexual leaders and the San Francisco mayor's decision to allow marriage licenses for gay couples.

By the group's accounting, it wins three-quarters of the suits it files, though it has lost some high-profile cases as well, including its efforts to order the reinsertion of a feeding tube for Terry Schiavo in Florida.

While some Christian groups have worked to influence legislation, ADF and similar organizations — including the American Center for Law and Justice and the Florida-based Liberty Counsel — are taking the cultural fight to the judiciary.

John Green, senior fellow in religion and American politics at the Pew Forum on Religion & Public Life, said rulings such as the landmark abortion case Roe v. Wade helped bring conservative Christians into politics.

Judiciary action is at least as important as electoral efforts to the overall movement, he said. "They've been very, very active in court," Green said.

ADF — founded by Focus on the Family's James Dobson, the late Bill Bright of Campus Crusade for Christ and others — started in 1993 to provide legal training and funding for cases involving issues that are important to religious conservatives.

Its initial focus was on training and funding cases brought by other groups or individual lawyers. But in the past several years, it has begun litigating more of its own cases because requests for legal aid are coming in faster than volunteers can handle them, and because cases taken by staff lawyers provide good training opportunities for law students and volunteers, said Paul Weber, ADF's vice president of communications and development.

Much of ADF's previous work has been focused on cases involving access or equal funding for Christian groups at universities or public schools. But as the debate over gay marriage has heated up, ADF has stepped directly into the fray.

It fought to have the nearly 4,000 marriage licenses issued to gay and lesbian couples in San Francisco revoked, saying the mayor had overstepped his authority and violated state law by allowing them. The California Supreme Court agreed.

The issue of gay marriage "kind of dropped out of the sky like a brick on your head," said ADF chief counsel Benjamin Bull.

"Like a fireman, we rushed to deal with it."

ADF now has a legal team dedicated to gay marriage cases.

Sears and the other lawyers at ADF are insistent that their arguments and lawsuits — though consistent with Christian tradition — also are rooted in legal principles and the Constitution.

The ADF and similar groups see the legal system and judges they deem "activists" as key drivers in shifting American culture away from Christian values. They often tangle with the American Civil Liberties Union.

Kevin den Dulk, a political science professor at Grand Valley State University in Michigan, said that while the ADF has been fairly effective in its legal strategies, it overestimates the influence of the judiciary on culture as a whole.

"Culture is generated in lots of ways," said den Dulk, who wrote his dissertation on the Christian right and the legal system.

The ADF now has more than 20 staff attorneys and 850 volunteer attorneys committed to donate at least 450 hours over three years. It hopes to increase those numbers to 100 staff lawyers and 5,000 volunteer attorneys in the next decade.