The controversy over the Catholic faith of Supreme Court nominee Amy Coney Barrett has exposed a fierce argument underway over the nature of American democracy. Two myths about the historical relationship of religion to liberal values—freedom, equality, justice, tolerance—are competing for dominance. Both must be resisted. For if the United States was not founded as a Christian nation, neither was it the product of a secular Enlightenment.

The great political thinker who first navigated between these two extremes was John Locke. Locke is considered one of the fathers of the liberal project, and his work influenced the American Founders perhaps more than any other writing outside of the Bible. His Two Treatises of Government (1689), in which he makes the moral case for rebellion against tyranny, is credited with igniting the American Revolution. But his writings on church and state have shaped the American Creed even more profoundly.

Even so, Locke’s conception of the role of faith in public life is as misunderstood by the religious Right as by the progressive Left, because unlike any other Enlightenment figure, he combined liberal political principles with a bracing commitment to the life and teachings of Jesus.

“Toleration of those that differ from others in matters of religion is so agreeable to the Gospel of Jesus Christ, and to the genuine reason of mankind,” Locke wrote in A Letter Concerning Toleration (1689), “that it seems monstrous for men to be so blind as not to perceive the necessity and advantage of it in so clear a light.” This was revolutionary stuff in 17th century Europe, where political and religious authorities alike enlisted the Bible to enforce orthodoxy and crush dissent.

Progressives see in Locke an Enlightenment skeptic who sought to check the baleful influence of religion on political life, and they celebrate him for it. They take his anti-Catholicism for granted, as an understandable prejudice against religious doctrines at odds with liberal principles. “Locke notably excluded Catholics from the religions meriting toleration,” New York Times columnist Elizabeth Bruenig wrote recently, “because he suspected they could not be trusted to leave their faith in the appropriate sphere.” Hence the infamous remark of Senator Dianne Feinstein during the 2017 hearings that led to Barrett’s confirmation to the U.S. Court of Appeals for the Seventh Circuit: “The dogma lives loudly within you, and that’s of concern.”

Like such progressives, many religious conservatives mistakenly believe that Locke swung open the door to the privatization of religion, and they despise him for it. They regard Lockean liberalism as the great enemy of morality, tradition, and faith. “Both politically and theoretically, hostility to the Church was encoded within liberalism from its birth,” writes Harvard’s Adrian Vermeule. Vermeule and other Catholic “integralists” seek a partial return to the idea of a “godly commonwealth,” in which government would promote explicitly Christian ideals and purposes. They worry that Barrett, under the influence of Locke’s ideas, will succumb to “the dominant liberal ethos of our age.”

Locke was indeed a severe critic of religious authoritarianism. “There is no such thing as a Christian commonwealth,” he declared. But he was no skeptic, either. His essentially Protestant outlook—revealed in his published works, journals, and private correspondence—emphasized the spiritual obligations that God’s love and mercy placed on every person.

In offering advice on child-rearing to his friend, Edward Clarke, for example, Locke urged parents to teach their children acts of devotion to God as the “Author and Maker of all things, from whom we receive all our good, who loves us and gives us all things.” He collected the sermons of his favorite ministers, produced a scholarly commentary on the New Testament epistles, and published a treatise defending the rationality of faith in Jesus as the Messiah. “It is not enough to believe him to be the Messiah,” he wrote in The Reasonableness of Christianity, “unless we also obey his laws and take him to be our king to reign over us.” A philosophical society he founded while in exile in the Netherlands had this rule for entry: “Proposing to ourselves and others the example of our Lord and Savior Jesus Christ, as the great pattern for our imitation.”

For Locke, Christian faith carried moral obligations as consequential to the public square as to private life. Both spheres, in Locke’s view, needed massive reform. Living during a period of renewed religious persecution and social unrest, he searched the Scriptures carefully for principles upon which to build a more just and stable society. His reform project began with a defense of the rights of conscience.

Locke collected every book and tract on religious freedom he could get his hands on. His personal letters are filled with references to the “dictates of conscience” and the importance of authentic faith. A 1688 journal entry under the heading “Tolerantia Pro” lists 21 passages from the Bible, including a climactic scene from Luke’s gospel in which Jesus asks God to forgive his executioners. Locke’s political outlook thus developed after decades of reflection on one of the central questions of our own age: How can we live together with our deepest differences?

The result was A Letter Concerning Toleration, a document of remarkable persuasive power, now considered part of the canon of the liberal-democratic tradition. Probably no other single work defending religious freedom exerted greater influence over the American mind.

Locke began the Letter with an indictment of intolerant religion, citing the humble example of Jesus as “the Prince of Peace” and “the Captain of our Salvation.” In the end, his political argument for freedom of conscience was inseparable from his Christology: a theology of charity and forgiveness, even toward those considered religious opponents and heretics. “The sum of all we drive at,” he explained, “is that every man enjoy the same rights that are granted to others.” By combining reason and revelation, Locke envisioned a political society framed by the golden rule: equal and impartial justice for all citizens, regardless of religious belief.

In his list of religious groups that deserved equal rights, Locke included some of the most persecuted religious minorities in Europe. “Nay, if we may openly speak the truth, and as becomes one man to another, neither Pagan, nor Mahometan, nor Jew, ought to be excluded from the civil rights of the commonwealth, because of his religion,” he wrote. “The gospel commands no such thing.” A lifelong member of the Anglican Church, awash with fears of “popish tyranny,” he nevertheless went on to argue that even Catholics deserved equal justice: “If a Roman Catholic believes that to be really the body of Christ, which another man calls bread, he does no injury thereby to his neighbor.” Written in the winter of 1685, just as Catholic France under Louis XIV had launched a campaign of intense persecution against the Protestant minority, it was a breathtaking claim.

The only set of ideas that did not deserve to be tolerated by a liberal regime, Locke argued, were those that threatened its very foundations. Militant religion, to be sure, was one such threat. This was a key reason Locke sought to separate church and state, “to distinguish exactly the business of civil government from that of religion.”

Yet, for Locke, more worrisome than the temptation to theocracy was the threat of atheism. “Promises, covenants, and oaths, which are the bond of human society, can have no hold upon an atheist,” he wrote. “The taking away of God, though even in thought, dissolves all.” Locke consistently denied toleration to atheists, a seeming contradiction of his otherwise principled arguments for pluralism. Yet only recently have political theorists decided that democratic societies must remain indifferent about God’s existence. Neither Locke, nor the American Founders, imagined that republican government could be sustained without the civic virtues that are nurtured by religious belief.

The Lockean view has found allies in high places. “Judges cannot—nor should they try to—align our legal system with the Church’s moral teaching whenever the two diverge,” Barrett wrote in a 1998 law-review article. “They should, however, conform their own behavior to the Church’s standard.” If confirmed, Barrett would replace Justice Ruth Bader Ginsburg, who was not shy in declaring that her Jewish faith profoundly influenced her approach to the law: “The demand for justice,” she wrote, “runs through the entirety of the Jewish tradition.” John Jay, the first chief justice of the Supreme Court and one of the authors of The Federalist Papers, would have agreed with her. Jay’s Christian faith anchored his own sense of justice, including his arguments for the abolition of slavery: “Till America comes into this Measure her Prayers to Heaven for Liberty will be impious.”

Locke’s wise and generous approach toward religious belief is embedded in our constitutional order—in the separation of church and state, in the First Amendment protections of religious liberty, and in the Constitution’s prohibition against religious tests for public office. But Lockean liberalism also inspired an ethos of freedom, pluralism, and equal justice. “I will not undertake to represent how happy and how great would be the fruit, both in church and state, if the pulpits everywhere sounded with this doctrine of peace and toleration,” he wrote.

For over 230 years, the pulpits of America have indeed resounded with this doctrine, helping the nation to turn religious diversity into a source of cultural strength and renewal—an achievement unmatched in the history of the world. Amid the fierce battle over Barrett’s confirmation, we’ll do well to remember that achievement and the necessity of preserving it.