The storied Anti-Defamation League, one of the nation’s oldest civil rights organizations, is fervent about the separation of church and state. It devotes an elaborate page to the subject on its website. It files friend-of-the-court briefs when church/state issues come before the federal or state judiciary. Whether the controversy is over school prayer, religious displays in public, or the phrase “under God” in the Pledge of Allegiance, ADL argues with much passion for keeping the “wall of separation” between government and religion as high and impenetrable as possible. “The more government and religion become entangled,” it has often warned, “the more threatening the environment becomes for each.”

No surprise, then, that ADL takes a hard line against school-choice voucher programs, which give parents the wherewithal to rescue their children from failing public schools and enroll them in private schools instead. Since those private schools are often church-affiliated, ADL contended in an amicus brief the last time the Supreme Court took up the issue, vouchers have the unconstitutional effect of directing “government funding to religious schools for religious purposes.”

That case was Zelman v. Simmons-Harris, a landmark decided in 2002 in which the Supreme Court disagreed with ADL. As long as vouchers enable parents to “exercise genuine choice among options public and private, secular and religious,” the majority ruled, nothing about them offends the Constitution.

But ADL’s opposition hasn’t softened. In a five-part essay posted online, it claims that “vouchers pose a serious threat to values that are vital to the health of American democracy” and “threaten to undermine our system of public education.”

Needless to say, the ADL position, widely shared on the left, has plenty of critics on the right, including your humble servant. From the conservative editorialists at the Wall Street Journal to the libertarian litigators at the Institute for Justice, supporters of vouchers have excoriated those who oppose them — especially teachers unions and the politicians who genuflect to them — for their willingness to keep poor kids trapped in wretched schools.

But while there may be nothing extraordinary about conservatives or libertarians embracing school choice, it takes real grit for liberals or Democrats to do so. Especially when they do so from within ADL.

Three months ago, the executive committee of ADL’s Philadelphia chapter voted overwhelmingly in favor of a resolution endorsing vouchers. Now it is urging the entire organization to follow suit.

“We believe school choice to be an urgent civil rights issue,” the committee argued in a brief being circulated among ADL’s 30 regional offices. Despite decades of increased spending on K-12 education, “the evidence that our public education system is failing to educate our children is staggering.” ADL should reverse its longtime position “as a moral imperative,” the Philadelphia leadership urges, and “issue a resolution in favor of school choice.”

As it happens, the ADL regional board isn’t the only liberal voice in Philadelphia calling for expanded school choice. State Senator Anthony Williams, a black Democrat and a candidate in Pennsylvania’s gubernatorial primary this week, is the founder of a charter school, a champion of vouchers, and an ardent believer in the power of competition to improve the quality of education. His position puts him sharply at odds with the state’s largest teachers’ union, which opposes choice and has endorsed his main opponent. But Williams — like the local ADL leadership — sees school choice as the great civil rights battle of the day.

“Anybody who was for Brown v. Board of Education — it baffles me that they would be against vouchers,” he told me last week. “Brown condemned schools that were separate and unequal. Well, that’s exactly what we’re back to now — schools that are segregated by income, by ZIP code, by race.”

Of the 20,000 children who annually enter Philadelphia kindergartens, he notes, almost half will drop out before finishing high school — and fewer than 2,000 will go to college. The way to fix the worst public schools isn’t to shower them with more money, he says. It is to empower parents to pull their children out and enroll them in better schools elsewhere.

Williams may not win the primary. Philly’s ADL chapter may not persuade the national board to follow its lead. But in swimming against the tide, both have set examples that will inspire others. Educational inequality persists, but thanks to some gutsy Philadelphia liberals, it has just lost a little more ground.