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President Obama’s longstanding refusal to say that the U.S. is at war with radical Islam was unaffected by the murder of four Marines and a sailor in Chattanooga. The president described the killer, Mohammad Youssuf Abdulazeez, as “a lone gunman,” while his secretary of defense, Ashton Carter, was apparently mystified by what he termed a “senseless act of violence.” Carter must have been aware of what the press was already reporting, that Abdulazeez had been blogging about radical Islam and showing other signs that his ultimate goal was jihad. Was the SecDef simply playing dumb, or was he following the example of a president who has sidestepped every opportunity to denounce radical Islam by name?

A clue to Obama’s reticence came last February when Homeland Security secretary Jeh Johnson revealed that the president had been asked by Muslim leaders in America to avoid linking Isis with Islam—presumably to prevent a violent Muslim sect from being associated with the religion in whose name it wages war. In April, however, with the al-Qaida massacre of 148 Kenyans who had been targeted for their Christian faith (Obama called it “terrorism”), this dubious excuse lost all credibility. Moreover, Muslim leaders in many countries have denounced radical Islam by name.

The Obama administration was temporizing on radical Islam long before Isis showed up. In 2009, the White House labeled the murder of 13 soldiers at Fort Hood by Nidal Malik Hasan—who shouted “Allahu Akbar” as he pulled the trigger—as “workplace violence.” When Congress asked Hillary Clinton about the attack in Benghazi, which happened on the anniversary of 9/11, the secretary of state played dumb. “Was it because of a protest,” she said, “or was it because of guys out for a walk one night who decided they’d go kill some Americans?” And so, in the shadow of Chattanooga, the question remains: why won’t Obama denounce radical Islam by name?

The search for plausible answers has challenged the explanatory powers of politicians, journalists, conspiracy buffs, and the blogosphere. Some agree with Donald Rumsfeld that Obama is “doing it for some mysterious reason of his own.” But are hidden motives needed? Obama is not the only one who refuses to look this war in the eye. In 2010, after a car bomb fizzled in Times Square, Mayor Michael Bloomberg was asked who might have done it. The mayor suggested that the failed attack might have been carried out “by somebody with a political agenda that doesn’t like the health care bill or something.” Not quite—the bomb maker was a Taliban-trained naturalized American citizen, who boasted in court that he was “a Muslim soldier.”

Bloomberg View columnist Eli Lake thinks that presidential aversion to the term “radical Islam” is rooted in strategic concerns that precede Obama. George W. Bush was careful to avoid those words because, the thinking went, the U.S. could only prevail in the struggle against terrorism by winning “at least the tacit support” of the radical-minded Muslims who were not at war with America (think Saudi Arabia). Immediately after 9/11, Colin Powell advised against seeing America’s almost 3,000 dead as “something done by Arabs or Islamics; it is something that was done by terrorists.”

For diplomats, needless to say, feigning ignorance is a required skill. But playing dumb about Isis and al-Qaida has spread through much of American and European society, and Australia, too. Last December, a known Islamist fanatic seized control of a café in Sydney. He forced his captives to display the Islamic creed and demanded an Isis flag. When asked if the assault was radical Islamic terrorism, Sydney’s commissioner of police said that he didn’t know.

Daniel Pipes scoffs at what he calls this “bogus state of confusion” and points to 20 years of press stories in which homicidal attacks by Islamic assailants have been falsely labeled as everything from “road rage” to an “attitude problem.” In 2006, the Los Angeles Times supplied a motive for a murderous assault by Naveed Afzal Haq on the Jewish Federation of Greater Seattle. The shootings, the Times story suggested, might have been caused by an “animus toward women.”

“The Mystery of ISIS,” an article in the August 13 issue of The New York Review of Books credited to an anonymous author with “wide experience in the Middle East” and who was “formerly an official of a NATO country,” looks into the history of radical Islam without ever using the word “radical” or examining its fundamentalist theology. “Anonymous” can’t understand what makes Isis tick, despite the movement’s proud assertions that its ruthless actions are justified and even required by Koranic scripture. “It is not clear whether our culture can ever develop sufficient knowledge, rigor, imagination, and humility to grasp the phenomenon of Isis,” Anonymous concludes. “But for now, we should admit that we are not only horrified but baffled.”

Not everyone puts the blinders on. In February, former MSNBC host Ed Schultz said the beheading of 21 Egyptian Christians by Isis “amounts to a religious war.” Senator Lindsey Graham has also called the struggle “a religious war” and challenges President Obama to be candid about the conflict. That’s not likely to happen. Obama’s main source of political support comes from secularized segments of the American population, mostly progressives who—unlike the working-class and Christian conservatives Obama despises—don’t “cling to guns or religion.”

Nevertheless, Obama and his fellow progressives do follow a moral code, which is usually described as Political Correctness (PC). They enforce their PC morality with an iron hand. Tell the PC gang that Bruce Jenner is not a woman, or that you’re a Redskins fan, or that all lives matter and—aided by accomplices in the mainstream media—they will label you a racist and run you out of town. But tell them you’ve just murdered four Marines and a sailor, and they’ll focus on your dysfunctional family. Tell President Obama four Jews were gunned down by an Islamic radical in a kosher market in Paris, and he’ll call the attack “random.”

On issues it deems crucial, such as climate change and gay marriage, PC wages relentless campaigns of moral indignation. One might think that PC would be eager to campaign against Koranic Correctness (KC), which advocates the opposite of everything PC holds dear. As enforced by Isis, KC allows slavery, the oppression of women, capital punishment, torture, intolerance, crucifixion, guns, child marriage, stoning adulterous women, and the execution of homosexuals. PC is “horrified” by KC’s return to the medieval beginnings of Islam. But instead of admitting that KC has declared religious war, PC professes only to be “baffled.”

Why does PC retreat into this contrived state of confusion? Possibly because finding oneself in a religious war without a religion is like being in a knife fight without a knife. Religion has long been a powerful motivator in human affairs and a moral armament on the battlefield. But PC, which considers itself too smart for theology, has been working overtime to eliminate any presence of religion in American life. Progressives can only strike at Isis with the PC weapons they use on Republicans. State Department spokeswoman Marie Harf suggested, for example, that Isis fighters might be deterred from their bloody work by a jobs program.

PC finds itself face to face with a mirror image of itself. It wants KC to be some kind of desert street gang that can be controlled by understanding the root causes of its rage. But alas for PC, KC has no interest in winning shouting matches on cable news. For KC, Islamic law is “settled science.” For 1,000 years, KC has had one rule for atheists: convert or die. In Paris, the survivors at Charlie Hebdo have promised not to publish any more images of the Prophet Muhammad.

PC shrinks from the fray. Progressives keep blaming George W. Bush and keep trying to see radical Islamic attackers as a “senseless” assortment of “lone gunmen.” They deny reality because KC enjoys what military analysts would call an “asymmetric advantage” over PC, which has unilaterally disarmed. KC doesn’t just cling to its religion and guns—it uses them. Progressives don’t play dumb because they are afraid to offend; they play dumb because they are afraid.