Khizr Khan, a Muslim immigrant whose son was killed while serving in Iraq, brought the Democratic National Convention to tears and raucous applause on Thursday when he held up his pocket Constitution and admonished Donald Trump: “Have you even read the United States Constitution? I will gladly lend you my copy.” Khan’s rebuke was, of course, a profoundly moving and very necessary rejoinder to Trump’s rampant Islamophobia. But that powerful moment, as well as Khan’s entire address, also revealed that after years of surrendering the issue to the GOP, Democrats have finally learned how to talk about and present a progressive vision of religious liberty.

Indeed, that very phrase—religious liberty—has become so freighted with discriminatory overtones that I hesitate to use it. The fight for “religious liberty” has come to dominate the Republican Party in recent years, through a series of campaigns that aim to promote prejudiced Christians’ freedom over everybody else’s. We saw conservative advocacy groups persuade the Supreme Court that for-profit corporations have a religious right to discriminate against female employees who wished to access contraception through their own health insurance. We saw Republicans endorse the idea that religious businesses should be able to refuse to serve same-sex couples. We’ve even seen laws that, under the banner of religious freedom, give mental health counselors and medical doctors the right to refuse to treat gay and trans patients.

In a clever act of doublespeak, Republicans have branded these measures “religious liberty”—but, as a federal judge recently pointed out, they really amount to Christian supremacy. (Or, more accurately, conservative Christian supremacy.) This attempt to legally elevate certain Christian beliefs above all others flatly contradicts the spirit and letter of the First Amendment, which was designed to protect religious belief and exercise while preventing the government from directly aiding religion or favoring certain creeds. Republicans’ “religious liberty” battle cry is also painfully hypocritical in light of the GOP standard-bearer’s repeated calls to forbid all Muslims from entering the United States. And a stunning number of Republicans who profess to support religious liberty also believe that the practice of Islam should be outlawed and the religion itself should be criminalized.

Khan’s address didn’t just throw this hypocrisy into stark relief; it demonstrated exactly how Democrats can seize true religious liberty as a winning issue for progressives. Consider Khan’s precise phrasing. “In this document,” he said, holding up his pocket Constitution, “look for the words liberty and equal protection of law.” Liberty and equality: Two constitutional guarantees that are intertwined and interdependent, each building on the other, each a critical component of freedom in a democracy. “Have you ever been to Arlington Cemetery?” Khan continued. “Go look at the graves of the brave patriots who died defending America. You will see all faiths, genders, and ethnicities.”

All faiths; all genders; all ethnicities: A beautifully diverse patchwork of Americans linked by their service to a country whose founding documents ensure liberty and equality for all by granting special rights to no one. An entire cemetery of soldiers—Christians, Muslims, Jews, atheists—who devoted their lives to protecting a country that dispenses justice evenhandedly, with preference for none and tolerance for all. Khan might as well have been paraphrasing U.S. District Judge Carlton Reeves, who blocked Mississippi’s anti-LGBTQ “religious liberty” law on both Establishment Clause and Equal Protection grounds, holding that it violated both “the guarantee of religious neutrality and the promise of equal protection of the laws.” In America, Reeves explained, religious freedom does not, cannot mean limiting the freedom of those who don’t share your beliefs.

In a Christian-majority country, Muslims’ best hope for liberty lies in this preservation of equality—the continued insistence that the government can neither discriminate against certain religions (as Trump would) nor license certain religions to discriminate against others (as Mississippi would). That is the Constitution’s vision of liberty as well, and it is precisely how Democrats should explain their own conception of religious freedom. My colleague Jamelle Bouie has written that the Democrats’ entire convention was infused with the spirit of the black church and its struggle for equality. In light of that tradition, it’s quite fitting that in his pointed and poignant address, Khan also infused the convention with the spirit of religious liberty and the First Amendment.

Read more Slate coverage of the 2016 campaign.