When the Philadelphia framers unveiled their proposed Constitution 225 years ago—September 17 will mark the official anniversary—most Americans were white Protestants. Anti-Catholicism ran deep, no Jews held high office, most blacks were enslaved, and the Church of Latter Day Saints did not even exist. Today, while America remains predominantly white and protestant, no white Protestant sits on the Supreme Court, which consists of five white Catholics, three white Jews, and one black Catholic. Among the four leading men now in the presidential/vice presidential spotlight, the only mainstream Protestant is black; two of the remaining three contenders are Catholic and one is Mormon. For this extraordinary evolution, credit the Constitution.

The place where the Constitution meets religion and race remains a treacherous cultural battleground. This spring, the conservative political operative and self-styled historian David Barton hit the bestseller list with an audacious new book on Thomas Jefferson’s philosophy of church, state, and race. Last week, Barton’s publisher unceremoniously withdrew this publication from store shelves, as scholarly evidence mounted that the book is bunk.

Barton’s fall is a cautionary tale about the perils of oversimplification. That said, here are three simple principles to remember regarding race, religion, and the Constitution.

Principle One: The Constitution is Not a Religious Document

Consider first what the Constitution’s pointedly does not say. Although the Declaration of Independence, the Articles of Confederation, and several Revolution-era state constitutions had explicitly and prominently invoked God in their opening and/or closing passages, the federal Constitution conspicuously said nothing of the sort. Thus, neither the Preamble nor any other constitutional clause explicitly mentioned the “Creator” or “Nature’s God” or “the Supreme Judge of the World,” as had the Declaration of Independence and the New York Constitution of 1777 (which incorporated the Declaration); or “the Great Governor of the World,” as had the Articles of Confederation; or the “Great Governor of the Universe,” as had the Pennsylvania Constitution of 1776; or “the Great Legislator of the Universe, ... the Supreme Being, the great Creator and Preserver of the universe,” as had the Massachusetts Constitution of 1780. The South Carolina Constitution of 1778 used the word “God” nine times—a word that explicitly appeared in every revolution-era state constitution save Virginia’s. But this word appeared nowhere in the federal Constitution—a pointed omission if ever there was one.

Consider next what the Constitution does explicitly say: “No religious Test shall ever be required as a Qualification to any Office or public Trust under the United States.” As of 1787, almost every state did in fact use religious tests. Nine states incorporated these tests into the very texts of their written constitutions. So the Framers’ emphatic rejection of religious tests for federal office-holders was not business as usual. It was big news—a truly revolutionary New World idea whose reverberations powerfully resounded last weekend, with a Mormon and Catholic clasping hands as thousands of onlookers—mostly mainstream Protestants—clapped and cheered.

Consider, finally, one additional patch of constitutional text, specifically focused on the presidency. While most Founding-era state constitutions expressly included the phrase “so help me God” or some analogous reference to “God” in their obligatory oaths, the Article II presidential oath omitted all mention of God. This omission was surely pointed and purposeful, with the result that no duly selected president could be obliged to utter the word “God” or profess his belief in any supreme being.

True, the Constitution does specially privilege “Sundays” in a clause governing the ten-day window for presidential vetoes, but this provision was not expressly theological; and common days of rest can be justified on wholly secular grounds.

One textual arrow might seem to point in a different direction. Immediately preceding the thirty-nine famous signatures at the bottom of the 1787 parchment, we find the following words: “done in Convention by the Unanimous Consent of the States present the Seventeenth Day of September in the Year of our Lord one thousand seven hundred and Eighty seven and of the Independence of the United States of America the Twelfth. In witness whereof We have hereunto subscribed our Names.” [Emphasis added.]

At first blush, these words might seem to contradict the central meaning of the religious test clause and the presidential oath clause. After all, the Constitution requires federal officials to take an oath to the Constitution itself. If that document really does proclaim that Jesus Christ is “our Lord,” then isn’t this oath-taking itself an improper religious test?

As it turns out—though this fact has until now not been widely understood—the “our Lord” clause is not part of the official legal Constitution. The official Constitution’s text ends just before these extra words of attestation—extra words that in fact were not ratified by various state conventions in 1787-88.

What, then, are we to make of these words? Just this: The words “our Lord” are much like the words “so help me God” in presidential inaugurations. No president can be obliged to utter these words in his inauguration ceremony, but presidents may choose to add them, if they wish. Over the course of American history, many presidents (and most modern presidents) have in fact chosen to add these words. Similarly, the Constitution nowhere requires a president to swear his oath of office on a Bible, but a president can choose to do so—and almost all presidents, beginning with George Washington, have in fact done so. Similarly, the thirty-nine framers at Philadelphia were allowed to profess their faith even in the public square. Some signers with quill in hand likely gave no thought to the “Year of our Lord” language and its theological overtones. But other signers may well have mused on things eternal, and on their personal relationships to God, at the precise instant when they added their names to a plan that they hoped would sharply bend the arc of human history toward justice. All of which leads us to our next general principle:

Principle Two: The Constitution is Not an Anti-Religious Document

A religiously neutral Constitution should not be confused with an anti-religious or anti-Christian Constitution. Just as no unbeliever may be barred from federal service for his atheism, no true believer may be excluded for his abiding faith.

Many of those responsible for America’s Constitution were folk of deep faith. Bracket, for a moment, the Founding generation. Whether or not Barton and his fellow travelers succeed in establishing that the leading framers wore religion on their sleeves, surely the generation of reformers who arose to stamp out slavery and its vestiges brought their faith dramatically into the public square. First and foremost, abolitionists believed that slavery was ungodly—and eventually they succeeded in inscribing their abiding moral principles in the Constitution itself, in a trio of Reconstruction Amendments adopted after the Civil War. Long before Barton, Ralph Reed, Jerry Falwell, and others made clear the clout of America’s religious right, America’s religious left—the abolitionist generation—gave us the Thirteenth, Fourteenth, and Fifteenth Amendments, the crown jewels of our Constitution.

And with these amendments in view, we see our final general principle:

Principle Three: The Constitution Includes More Than the Founding

Two hundred and twenty-five years ago, slavery, race discrimination, and/or religious tests prevailed in most states. Today, all races and religions stand equal before the law, and do so not because activist federal judges have plucked liberal constitutional principles out of thin air, but because We, the People of the United States, amended our Constitution after the Civil War to hold state governments to much higher standards of religious and racial equality. None of the four men who now stand atop the political pyramid could have scaled these heights had the rules of 1787, grand as they were for their time, remained unchanged. As America celebrates the Constitution’s 225th birthday, let’s give credit not just to the Founders but also to those later generations who, thank God, made amends for some of the sins of our fathers.

Portions of this article are based on Akhil Reed Amar's forthcoming book, America’s Unwritten Constitution: The Precedents and Principles We Live By.

Editor's note: The original version of this article stated that most presidents chose to omit "so help me God" from the presidential inauguration. It should be most modern presidents.