Firms are loathe to admit it, but pro bono is political, and in the vast majority of cases, it skews left. Arguably, pro bono is by nature liberal. Assisting the indigent, immigrants, murderers, and the dispossessed—the usual pro bono fare—are not for lovers of the status quo.

So where does that leave conservative pro bono? Well, it depends on the cause. Big firms have few qualms about advocacy for economic conservatism. "We actively seek out libertarian cases," says Michael Williams, a partner at Kirkland & Ellis in Washington D.C. He says these cases often involve challenges to regulation, especially for entrepreneurs who face outdated, unfair regulatory schemes.

Far less acceptable is pro bono that promotes conservative culture, such as restrictions on abortion and the promotion of traditional marriage or religion. "We'd approach big firms and find willing individuals to take our cases only to be told that the firm won't get involve," says Horatio Mihet, chief litigation counsel for Liberty Counsel, an organization that fights for religious freedom. "You end up wasting a lot of time." As a result, Mihet says his organization and similar ones, such as Alliance Defending Freedom, have developed their own sizable legal staff or turned to smaller firms for help.

A few big firms have supported sensitive conservative causes—but they aren't bragging. Former Orrick, Herrington & Sutcliffe partner Samuel Casey, an anti-abortion activist, says Gibson Dunn & Crutcher provided critical help in getting the Bush administration to ban embryo research. Though Gibson never officially appeared on behalf of the anti-abortion group, says Casey, "it was largely led by Gibson lawyers." In particular, he lauds Gibson Dunn partner Thomas Hungar, former deputy U.S.solicitor general, for assisting on pro life matters. (The firm's pro bono coordinator Scott Edelman says Gibson Dunn also represents Planned Parenthood and that "the vast majority of our pro bono work would be characterized as liberal.")

Another prominent, but much smaller, firm that takes on controversial right-wing causes is Washington, D.C.'s Bancroft, where former solicitor general Paul Clement is a partner. Clement jumped over from King & Spalding in 2012 when it refused to let him take on the defense of the Defense of Marriage Act. At the time, Clement issued a statement that his defense of DOMA was not necessarily a reflection of his own opinion but that the act deserved a vigorous defense.

Bancroft seems to be practicing what it preaches. Recently, Clement scored a Supreme Court win for Little Sisters of the Poor, challenging the contraceptive mandate under the Affordable Care Act for religious orders. Despite the firm's conservative reputation, it takes on its share of liberal pro bono cases too, says Erin Andrews, a Bancroft partner, citing work for criminal defendants and illegal immigrants. "We like to play against type; if it's a good case, we'll take it," she says. "Large firms are more reluctant because they face different pressures."

Though some firms might take on cases that chip away at contraception or abortion under the cloak of religious liberty, it's unthinkable that a major firm would touch anything that could diminish gay rights. Indeed, once Republican stalwart and Gibson Dunn partner Ted Olson joined forces with David Boies in the fight to defeat California's Proposition 8 (which banned gay marriages ), it was clear that the legal establishment was on the side of LGBT rights. (Olson is now spearheading transgender rights, seeking to defeat North Carolina's law that requires people to use public restrooms based on the gender on their birth certificates.)

This institutional embrace of liberalism is what makes some conservative lawyers feel excluded. Roger Gannam of Liberty Counsel says he left his job with a large Atlanta-based firm because he was discouraged from doing Christian advocacy. Now the lead counsel for Kim Davis, the Kentucky clerk who made headlines for refusing to issue marriage licenses to gays, Gannam says, "there's cultural bias against Christians " in Big Law that has worsened in recent years. "The culture has changed in the last five or six years—with same sex marriage, and now transgenderism. It lends to the view that conservative causes like traditional marriage are not mainstream."

Olson probably agrees. And that, he suggests, is precisely the point: "Attitudes about [the LGBT community] have changed profoundly in a short time. Law firms and companies have to think about the business implications of their actions, particularly if you're making your employees uncomfortable."

 vchen@alm.com