Portrait of Thomas Jefferson by Matthew Harris Jouett. In a Republican primary season that has stoked fears of the undesirables and the undocumented in our midst, it now seems to be the Muslims’ turn.

In a Republican primary season that has stoked fears of the undesirables and the undocumented in our midst, it now seems to be the Muslims’ turn.

Last week, Donald Trump let slide the comments of a man at a New Hampshire town hall meeting who called President Obama a Muslim, described Muslims as “a problem in this country,” and suggested it was time to “get rid of them.” On Sunday on Meet the Press, Ben Carson described Islam as inconsistent with the Constitution and said he “absolutely would not agree” with putting a Muslim in the White House.

When questioned about these controversies, neither man backed down. Trump tweeted that he was not “morally obligated to defend the president.” Carson told The Hill that the next president should be “sworn in on a stack of Bibles, not a Quran.” Repeatedly, Carson raised the specter of Muslims lying about their own faith in order to achieve their political aims — a notion many “birthers” have used to explain how a president who repeatedly calls himself a Christian could somehow be a secret Muslim.

Unfortunately, none of this is new. Americans like to think of our country as a nation of immigrants and a nation of religions, but repeatedly we have failed to live up to our ideals, banishing fellow citizens from the American family because of their ethnicities or religious commitments.

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Throughout U.S. history, Protestants have denounced Catholics as fake Christians, amoral villains and traitors to the nation. In an argument that anticipated today’s critiques of Islam, inventor Samuel Morse argued in 1835 that the ideal of religious liberty served as a Trojan horse secreting enemies of the nation “into every nook and corner of the land.” This “infallibly intolerant” Roman Catholic tradition, he argued, wasn’t even a religion; it was a nefarious political scheme masquerading as one.

But anti-Catholicism was not the only culture war prosecuted by conservative defenders of faith and flag. Mormons, too, were targeted as slaves of a religious despot whose liberty was incompatible with our own. Before this culture war was over, Mormon leaders would be sued, jailed, beaten, stripped naked, tarred and feathered, and murdered. And rank-and-file Mormons would be chased from New York to Ohio to Missouri to Illinois to the Utah territory.

President Obama speaks at Adas Israel Congregation in Washington on May 22, 2015 as part of Jewish Heritage Month. Photo courtesy Ron Sachs

Today, it is easy to imagine that Barack Obama is the first U.S. president to be accused of being a Muslim. But that honor actually belongs to Thomas Jefferson.

Jefferson’s face now adorns Mount Rushmore, but in the election of 1800, Federalist partisans of John Adams viciously denounced Jefferson as un-American, principally because of his unorthodox faith, which ran more toward deism and Unitarianism than toward evangelical Protestantism.

One Federalist called Jefferson the “great arch priest of Jacobinism and infidelity.” The Connecticut Courant suggested he might be a secret Jew or Muslim. It complained that no one seemed to know “whether Mr. Jefferson believes in the heathen mythology or in the alcoran (Quran); whether he is a Jew or a Christian; whether he believes in one God, or in many; or in none at all.”

There was talk at the founding of turning the United States into an officially Protestant nation, and during debates over the Constitution, some in the states raised the specter of a Catholic, “infidel,” or “Turk” (an epithet for “Muslim”) holding office. But the founders wisely decided on a godless Constitution with no religious tests for national office.

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This expansive design has served the country well. It has not prevented Americans from imposing their own religious tests for political office, or from waging cultural warfare on religious minorities, but in the long run these disputes have typically been resolved in the direction of liberty. We no longer worry that Vice President Biden is a Catholic, that Mitt Romney is a Mormon, or that Ben Carson is a Seventh-day Adventist. In fact, Rep. Keith Ellison, D-Minn., made history in 2007 by becoming the first Muslim member of Congress and took his ceremonial oath with a Quran once owned by Jefferson.

Stephen Prothero, a professor of religion at Boston University, is the author of the forthcoming book Why Liberals Win the Culture Wars (Even When They Lose Elections. Photo courtesy of HarperSanFrancisco

Although our candidates are sometimes mum in the face of religious bigotry, our values cry out against it. On this question, Carson’s own church is clear. Its website states that “the Seventh-day Adventist church strongly believes in religious freedom for all people.” Happily, Americans have traditionally said “Amen” to that. As the ongoing culture war on Islam proceeds, will Trump and Carson do the same?

Stephen Prothero, a professor of religion at Boston University, is the author of the forthcoming book Why Liberals Win the Culture Wars (Even When They Lose Elections).