On Monday, the Tennessee state Senate approved a bill designating “the Holy Bible” as the official state book—a measure that, as the state attorney general has noted, obviously violates the Establishment Clause of the First Amendment. The bill, which drew bipartisan support, will now go to the governor for his signature. It is distressing to see a Legislature push through a bill that unconstitutionally endorses Christianity over all other religions. But what’s more disturbing is the Senate’s justification for the measure: The idea that, as one senator explained, “the very founding of our nation, the very form of government we have to today,” is “based on … Holy Scripture.”

Contrary to the Tennessee Legislature’s belief, the United States Constitution is not grounded in the Bible, and the framers were not ersatz priests crafting a knockoff scripture. Rather, the framers were political theorists who based their own founding charter on a combination of natural law, classical republicanism, and constitutionalism. The primary inspirations for the Constitution they ultimately penned were social contract theorists like Thomas Hobbes, John Locke, and Jean-Jacques Rousseau. Locke’s vision of natural law was especially influential: He believed that people were born with inalienable rights, namely life, liberty, and property, and that the government’s primary purpose was to protect these rights.

Locke was undoubtedly influenced by Christianity, but as an Enlightenment philosopher, he hoped for a civil state, marked by religious tolerance, with sovereignty rooted in the people. (His work was largely a rebuttal to the “divine right of kings,” the theory that all social ranks must obey monarchs because their power is derived from God.) If Christianity was critical to Locke’s vision of social equality, it was anathema to his conception of governance: The state, he insisted, must be secular, wholly independent from the church. Still, Locke did believe that a deity bestowed humanity’s natural rights—an intuition that Thomas Jefferson stated explicitly in the Declaration of Independence. Writing nearly a century after Locke, Jefferson declared that “all men are created equal” and “endowed by their Creator with certain unalienable Rights.”

Because the Constitution itself does not mention God—except for its idiomatic time stamp, “in the Year of Our Lord”—social conservatives often cite Jefferson’s “Creator” language as proof that America’s founding documents look favorably upon Christianity. But Jefferson, like many of the founders, was skeptical of both government entanglement with religion and Christianity itself. (His famous “Jefferson Bible” excluded any mention of Jesus’ divinity.) The framers had witnessed the bloody conflicts that inevitably erupted when the state took sides in religious disputes. So in the First Amendment to their new Constitution, they included the Establishment Clause, barring Congress from passing any law “respecting an establishment of religion.” In Jefferson’s words, the clause was designed to build “a wall of separation between Church & State.”

Like the rest of the Bill of Rights, the Establishment Clause initially applied only to the federal government. That allowed Southern states to enact laws recognizing a pro-slavery version of Christianity as a valid religion—and prohibiting anti-slavery interpretations of religion. Under this legal regime, Southern states effectively respected racist Christianity as an official religion. The predictable result was a crackdown on any contradictory religious beliefs. In response, after the Civil War, the framers of the 14th Amendment applied the Establishment Clause to the states, forbidding them, too, from endorsing religion.

And that, of course, is exactly what Tennessee now hopes to do by elevating the Bible to a special status above all other holy books. As Tennessee’s attorney general already explained, “Legislative designation of The Holy Bible as the official book—as an official symbol—of the State of Tennessee, when viewed objectively, must presumptively be understood as an endorsement of religion and of a particular religion.” Greg Lipper, senior litigation counsel at Americans United for Separation of Church and State, agrees: “The most cardinal of Establishment Clause sins,” he told me on Wednesday, “is for the government to promote one religion over others.”

This principle isn’t some newfangled invention of a liberal Supreme Court. It is a core belief of the men who drafted the Constitution, who understood that entanglement between church and state cheapens both. (Some legislators supported the bill but insisted that they were only honoring a historical text—as though the Bible is little more than some old book.) Jefferson might not have guessed that a state would someday wish to honor the Bible by placing it among the raccoon (official state wild animal), the square dance (official state folk dance), and the Barrett M82 (official state sniper rifle). But he and his fellow framers knew that the best way to respect religion was to keep government out of it—and vice versa. Now, more than two centuries later, the Tennessee legislature is eager to prove just how right they were.