On Sunday, I laid out my case for why I believe Robert Jeffress, a prominent Southern Baptist pastor, was irresponsible when he insisted that Mitt Romney’s Mormonism, which Jeffress deemed to be a “cult,” should be a key factor in voting against Romney in the GOP presidential race.

The Jeffress episode is a good opportunity to reflect on why the American Constitution, in Article 6, Clause 3, says this: “The Senator and Representatives before mentioned, and the Members of the several State Legislatures, and all executive and judicial Officers, both of the United States and of the several States, shall be bound by Oath or Affirmation, to support this Constitution; but no religious Test shall ever be required as a Qualification to any Office or public Trust under the United States.” [emphasis added]

About this article and clause several things may be said, beginning with this: The language used by the framers was as emphatic and unqualified as any you will find in the Constitution. The reason is simple: they knew how explosive (as well as important) the mix of religion and politics could be, and therefore insisted we prevent any kind of religious test from ever taking root in American soil.

It’s perhaps worthwhile to recall the brief history of James Madison, the so-called “father” of the Constitution and arguably primus inter pares among the founders. In Virginia in the 1780s there was an effort to raise taxes to support teachers of the Christian religion. Although the Virginia Bill of Rights (which Madison had in hand) had ended religious establishment in that state, several influential figures believed the well-being of religion required state support. (For a full account of this matter, see James Madison: A Biography, by Ralph Ketcham.) Madison thought it was “obnoxious on account of its dishonorable principle and dangerous tendency.” Madison was worried that this would, in Ketcham’s words, “violate the natural rights to liberty of conscience and involve the state in questions of heresy and orthodoxy entirely outside its realm.”

In order to channel the opposition to this tax, Madison drafted a “Memorial and Remonstrance Against Religious Assessments,” which argued, among other things, that “ecclesiastical establishment” not only didn’t promote religious purity but nearly always corrupted it. The assessment was a step toward bigotry, differing from “the Inquisition … only in degree,” and would make Virginia no longer an asylum for the persecuted. “Religious liberty stands out as the one subject upon which Madison took an extreme, absolute, undeviating position throughout his life,” according to Ketcham.

Which brings us to the Constitution itself. During the ratification period, the No Religious Test clause was used as ammunition by the anti-Constitutionalists. But the framers would not budge; for them, the issue was paramount. And the great 19th century legal scholar Joseph Story, in his magisterial Commentaries on the Constitution, explained why.

“This clause is not introduced merely for the purpose of satisfying the scruples of many respectable persons, who feel an invincible repugnance to any religious test, or affirmation,” according to Story.

It had a higher object; to cut off forever every pretense of any alliance between church and state in the national government. The framers of the Constitution were fully sensible of the dangers from this source, marked out in the history of other ages and countries; and not wholly unknown to our own. They knew that bigotry was unceasingly vigilant in its stratagems, to secure to itself an exclusive ascendancy over the human mind; and that intolerance was ever ready to arm itself with all the terrors of the civil power to exterminate those who doubted its dogmas or resisted its infallibility.

Story went on to remind his readers of the history of other countries, where they “found the pains and penalties of non-conformity written in no equivocal language, and enforced with stern and vindictive jealousy.”

I recount this simply to remind us that religious liberty depends on religious tolerance, and injecting sectarianism into politics has an ugly history. There are certain civic wounds that one doesn’t want to reopen.

America has achieved something remarkable in the history of nations: allowing religion to play a constructive role in the public square in a way that honors both faith and politics. It isn’t an easy balance to achieve, to say the least; and we have achieved it better than anyone. And so we don’t need ministers of any faith, including Christianity, attempting to undo what the framers created, with such great care and wisdom.