Last week, Iran’s supreme leader, Ayatollah Ali Khamenei, accused the U.S. government of orchestrating the desecration of Qurans. Clearly facts are irrelevant to Iranian leaders as they seek to crank up anti-American outrage over a Quran burning that never occurred.

Facts are also irrelevant to Islamists in Afghanistan, Pakistan, and Kashmir, who magnified the threat of an insignificant Florida pastor into an alleged U.S. crusade against Islam. In Third World countries full of poor, illiterate people with no access to solid information, it’s easy for demagogues to get them to blame their troubles on the West.

What’s harder to understand is why so many conservatives in this country seem determined to imitate the ayatollahs, using rumors and lies to whip up hatred of all Muslims. Not only does this fearmongering play into the hands of radical Islamists, but it also tears at the fabric of American society as a whole.

A flurry of fact-twisting has characterized the whole debate over whether an Islamic center should be built two blocks from Ground Zero. The question of the center’s location pales beside the way the issue has been misused to stir up hatred of American Muslims as a group.

Whether or not you agree fully with the views of the center’s promoter, Imam Feisal Abdul Rauf, there is no question he’s a proud American and a moderate Muslim. He was sent abroad as an emissary of interfaith dialogue by the Bush and Obama administrations. And he’s now said he is open to all options on the mosque’s location, hardly a radical approach.

Moreover, there was minimal controversy over the proposed center when the issue first became public. Example: Conservative media maven Laura Ingraham, guest-hosting The O’Reilly Factor on Fox News in December: “I can’t find many people who really have a problem with it.”

Once a couple of well-known conservative bloggers started hyping the issue, however, backed by the New York Post and Fox News, the mosque location became the excuse for an outright Islamaphobic campaign.

It’s no accident that one of the bloggers, Pamela Geller, heads a group called: Stop Islamization of America. She once reprinted a post insinuating President Obama was the illegitimate son of Malcolm X. Geller’s theme, that Muslims are scheming to take over the country, and the mosque is their symbol, has suddenly become a leitmotif of the political season. Even Ingraham has now disavowed the mosque.

Prime among the Islamaphobes is Newt Gingrich: He said on Fox last month that “the folks who want to build this mosque are really radical Islamists” whom he compared to Nazis seeking “supremacy” in the United States. For good measure, Gingrich charged Obama with “pandering to radical Islam.” This dovetails with the anti-factual conservative campaign that has convinced 18 percent of Americans the president is a Muslim.

Another typical example of inflammatory GOP rhetoric came from State Rep. Rex Duncan of Oklahoma, who warned of a “war for the survival of America,” because Muslim sharia law was threatening the Constitution. There are too many similar examples to quote here.

This scary political climate, in which Sarah Palin fuels the flames, has so spooked mainstream Republicans that they appear loath to tamp down the anti-Muslim rhetoric. Meantime, in the background, Rush Limbaugh keeps up the phobic beat and fundamentalist preachers such as Pat Robertson warn that Muslims are on the verge of “taking over.”

I know we’ve had religious prejudice in this country before. But this is something different. In the age of talk radio and the blogosphere, when many Americans are fearful about economic and social changes, receptivity to demagoguery is increasing. When times are tough, it is tempting to seek a scapegoat. Gingrich recognizes that as readily as does Ayatollah Khamenei.

Yet it is vital that Americans distinguish between the real threat — radical Islamic groups and movements in many Muslim countries — and the hyped-up threat promoted here.

For one thing, the fearmongering helps radical Islamists. Gen. David Petraeus just warned that videos of Quran burning could endanger our troops overseas. What would be even more dangerous is if the Islamaphobes provoke a war of civilizations within the United States — the very outcome the jihadists seek.

We are a nation of immigrants, in which Muslims of Arab, South Asian, and African descent have flourished. This is why Muslims in America are so well-integrated, unlike in Europe, where many Muslim immigrants have failed to assimilate.

There will be exceptions, such as the Pakistani American who tried to put a bomb in Times Square. But preventing such disasters will be far easier if new Muslim Americans are made to feel welcome and encouraged to speak up about any suspicious activity in their communities.

Bottom line: I can’t believe most Americans want to stoop to the level of ayatollahs and jihadists. Shame on Newt Gingrich; shame on those who play on Americans’ anxieties. Let’s call out the bloggers, pundits, and pols who are trying to drag us down.

— Trudy Rubin is a columnist and editorial board member for the Philadelphia Inquirer. trubin@phillynews.com