Is the “Ground Zero Imam,” Feisal Abd ar-Rauf, a moderate Muslim? I do not know. I have yet to read his books or peruse his speeches and sermons in all the languages that Mr. Rauf uses. Some of his short essays and interviews in English suggest that he is a preacher of moderate disposition and views. But some of his more tentative, if not deceptive commentary about terrorism against Israelis, America’s culpability for 9/11, and the nobility and value of the Holy Law for Muslims living in the West suggest something different.

I have a sneaking suspicion that those who have risen in high dudgeon against critics of the Cordoba Initiative’s “Ground Zero mosque”—for example, Peter Beinart, Richard Cohen, Fareed Zakaria, and Matthew Yglesias—may also not have done much due diligence on Mr. Rauf. (If they have done so, but have chosen not to reveal their homework in their writing, I apologize.) I can certainly appreciate why devout partisans of religious freedom have recoiled from some of the harsh and philosophically-chaotic commentary opposed to a mosque anywhere near Ground Zero. However, building an Islamic complex where the Twin Towers collapsed is different from building a mosque on Massachusetts Avenue in Washington, DC. With the latter, we may frown on monies flowing to it from Saudi Arabia’s Wahhabi establishment, given Wahhabism’s virulently anti-Western, anti-Semitic, and just all-around anti-fun traditions, but we certainly would not try to shut it down.

But standards for judging Mr. Rauf and the Cordoba Initiative should be different. Charles Krauthammer is right: Ground Zero is sacred ground. It would be morally obscene to allow Muslims to build a center near Ground Zero who had not unequivocally denounced (renounced, would be okay, too) the ideas that gave us the maelstrom of 9/11. If Mr. Rauf has collected monies from individuals or Muslim organizations overseas that preach contempt for infidels, have financially supported religiously militant organizations, or, worse, provided aide to the families of Palestinian suicide bombers, then his project, which has been approved by Mayor Michael Bloomberg, ought to be cancelled. Any American non-profit organization can tell you exactly whence its money comes. By contrast, it appears that the Cordoba Initiative’s funding has not been cross-checked with financial counterterrorist information within the Treasury Department, the Federal Bureau of Investigation, and the Central Intelligence Agency. (If it had been, we probably would have heard about it.)

We also might wonder whether Mayor Bloomberg has asked for and received any alarming information from the FBI and the CIA about Mr. Rauf and his organization (Republican and Democratic members of either the House or Senate select committees on intelligence could do likewise, and receive a much fuller accounting of any information, and then relay, with due attention to Mr. Rauf’s privacy, a “yes” or “no” about any damning intelligence within classified files).

As any American or European counterterrorist officer can tell you, there is often a bewildering matrix of Islamic charities and financial institutions that knowingly, and unknowingly, funnel monies for terrorist groups and radical organizations. Mr. Rauf may be unfairly thought guilty by association; if so, he most of all should want to know whether he has received funds from Muslims who do not believe in peaceful coexistence with the West.

So we need to know whether Mr. Rauf is a moderate Muslim. Who—or what—is a “moderate Muslim” isn’t an easy question to answer. A moderate believer in the Iraqi holy city of Najaf isn’t the same as a moderate Muslim in the down-and-out suburbs of Paris. Moderate American Muslims, given the cultural traditions and moral expectations in the United States, would be different from moderate Muslims in the Persian Gulf (Mr. Rauf was born in Kuwait), where, depending on the country, an unveiled Muslim woman is a profound provocation.

Mirror-imaging themselves onto foreigners, Americans on both the left and the right are usually pretty quick to see moderate Muslims everywhere (George W. Bush and Barack Obama differ little here). Historically, Muslims themselves have shied away from splicing and dicing the faith in secular Western ways. The Ottomans viewed the jihad-happy, shrine-destroying, Shiite-killing Saudi Wahhabis as being beyond the Islamic pale; when a historian hits the words ghulat or ifrati—both denote “extremism”—in chronicles, he knows the author is probably discussing Muslims who are outrageously violent or proselytizing unholy ideas, like a Sufi lord, a pir, becoming a god-head.

But non-Muslim Americans need not, of course, define “moderation” as would faithful Muslims with a respectful eye to the past. We get to use American definitions for anything that happens on American soil. As de Tocqueville noted, faith in the United States is a civil creed: Americans have always put limits on what is acceptable in the communications between God and man. American Protestants and Catholics got to tell Mormons that despite their divine text messaging, polygamy and racism were taboo. (Today’s American secular elite has obviously gotten a bit lax about polygyny.) American Jews get to cross off the “moderate list” anyone who describes the children of Abraham as “Christ-killers.”

So what might be an American definition of a “moderate Muslim?” Perhaps the following two entries would be a good place to start.

(i) a believer who unqualifiedly rejects terrorism against anyone. This is America’s Eleventh Commandment. If a Muslim cannot renounce terrorism against Israelis, that person should not be allowed to build an Islamic center near Ground Zero. Testing for unacceptable deviancy isn’t hard. Just borrow from the former al-Qa’ida philosopher, Abd al-Qadir bin Abd al-Aziz, aka “Dr. Fadl,” who sees Palestinian suicide bombers as destined for hell. Thus: “Do you, Feisal Abd ar-Rauf, believe that Allah damns eternally Palestinian suicide bombers?” “Do you believe that rockets launched at Israeli towns by Hamas and Hizbollah are acts of terrorism, which will bring down upon the perpetrators Allah’s wrath?” Mr. Rauf’s answers ought to be short.
(ii) a believer who embraces the doctrine of “neo-ijtihad,” which holds that Muslims today are not chained to the Qur’anic interpretations and legal decisions accepted centuries ago as canonical. Specifically, a “moderate Muslim American” is someone who unqualifiedly renounces the applicability of the Sharia, the Holy Law, in American society. The “Americanization of Islam” here means that the traditional Muslim understanding of orthodoxy as orthopraxy (it’s not what you believe in your heart—that is between you and God—but how you act, i.e., apply the Sharia, in the public square that matters) is null and void. Thus, women may veil or not veil as they please; a woman’s testimony is equal to a man’s; polygyny is verboten; marriage to a menstruating child is an abomination; accepted corporalpunishments—amputations and stonings—are immoral; apostasy reflects bad judgment but isn’t criminal; and Jews and Christians should spiritually no longer be viewed as dhimmis, a properly subordinate species who really don’t deserve the same social status and legal rights as Muslims. Jewish and Christian power in America and Europe isn’t an offense against the divinely-sanctioned natural order; it’s just the product of a long, difficult, and tortuous evolution. The Sharia is a lengthy and complicated corpus that developed over centuries and often constrained the worst instincts of despots. A “moderate Muslim American” would see it in much the same way that a faithful “moderate Jewish American” views the Old Testament and the Talmud: documents of a certain time that contain considerable “divine” wisdom (as well as much looniness) and many imperatives for a good, healthy life.

If Mr. Rauf can so define “moderate Islam,” he may not be as American as apple pie, but he would certainly be as American as much of New York City. Any mosque built by such a believer would honor us all.