Presbyterian minister Carl Trueman.

Photo: Grove City College

Carl Trueman is a distinguished scholar, bestselling author and ordained Presbyterian minister. On Aug. 7 he gave a series of talks to the Sacramento Gospel Conference, live-streamed on the YouTube channel of Immanuel Baptist Church. Twice during the event, the live broadcast was booted off the air. Viewers were informed that the first interruption was due to a copyright violation, possibly the result of Christian music that the conference organizers played during a break. But in the second, more mysterious instance, Mr. Trueman’s presentation went dark because of a “content violation.”

Was this an intervention by a human being or an algorithm on automatic pilot? Neither Mr. Trueman nor Immanuel Baptist has been told. Equally unclear is the specific nature of the alleged content violation. Nothing in Mr. Trueman’s talks encouraged hatred, vulgarity or violence. On the contrary, he offered a thoughtful analysis of American cultural attitudes toward sex through the lens of classic Christian thought, citing sources from Freud to the philosophers Rousseau and Charles Taylor.

Mr. Trueman is understandably worried that religious speech is being censored online. So are many other religious believers. And for good reason: We sense that the First Amendment guarantee of religious liberty is being dismantled, and with it the profound contributions that religion makes to American unity and self-government.

Today’s sexual politics function as a new kind of fundamentalism, one that presents a deep problem to a diverse and democratic society. Instead of encouraging the dialogue of democratic process, the fundamentalists seek to impose their own rigid certitude unilaterally. On matters ranging from foster care and education to gender ideology and the family, this new fundamentalism is displacing the moral convictions that once grounded U.S. culture. The result isn’t a more compassionate and liberal society; it’s a more punitive one.

Social media enables the new fundamentalism, enforced by the mysterious rules of Big Tech’s quasimonopoly. On public sidewalks, the First Amendment still theoretically protects free speech. In the new public square of the internet, power displaces liberty and conscience.

In the past, religious-liberty issues could be resolved, or at least fruitfully argued, by appeals to the Founding. The Founders’ moral vision was shaped by a mix of biblical faith and Enlightenment thought: reason and faith working together. This vision was once widely shared but lately has less force. And here’s why: The language of “rights” and social justice that marks so much of today’s social unrest may sound familiar—and much of it is a response to real injustice—but some of the key ideas that govern our current culture wars are found nowhere in the Constitution, or, for that matter, in reality. We can locate them instead in the work of thinkers like Herbert Marcuse and his 1965 essay “Repressive Tolerance.”

As the cultural turmoil of the 1960s began to unfold, Marcuse wrote that “what is proclaimed and practiced as tolerance today” is actually “serving the cause of oppression.” Thus, a “liberating tolerance” might require “new and rigid restrictions on teachings and practices which . . . serve to enclose the mind within the established universe of discourse and behavior.” In other words, intolerance in the service of a new and allegedly “liberating tolerance” is not only acceptable, but praiseworthy. Killing freedom in the name of freedom is the Orwellian proposition at work.

This is why religious liberty should be important to everyone. It checks government’s tendency to overreach, and it helps form citizens in the virtues necessary for democracy to work. There is a reason the Pledge of Allegiance places our national loyalty “under God.” Without that protection, the ambitions of power tend to corrupt conscience and deform human rights.

As writers, we speak from two different branches of the Christian tradition. Yet as Christians we share an obligation to hear those who suffer, to work for justice and speak the truth with love. St. Paul’s Epistle to the Romans reminds us to respect and obey civil authority, and to be leaven for goodness and beauty in the world. Here in the “new Rome,” the task remains the same.

The American experiment was founded on, and has always thrived on, the freedom of religious believers to speak, teach, preach, practice, serve and work in peace—not only in private, but in the public square—for the truth about God and humanity that ennobles their lives and all lives.

The more we diminish that freedom, the more crippled we become as a people. The more we feed it, the deeper and more robust the roots of our nation and its freedoms grow. Those are the two paths before us. Here’s the good news: We get to choose.

Archbishop Cordileone leads the Catholic Archdiocese of San Francisco. Mr. Daly is president of Focus on the Family.

Wonder Land: With social media platforms like Facebook and Instagram, we have democratized neurosis. Images: Getty Images/Walt Disney via Everett Collection Composite: Mark Kelly The Wall Street Journal Interactive Edition