After heavy criticism of its decision to invite Franklin Graham to preach during the National Day of Prayer at Defense Department headquarters, the Pentagon just withdrew its invitation. The evangelist became persona non grata after groups protested his denigration of Islam, which he has described as “wicked”, “evil” and “violent.”

Sarah Palin and Erick Erickson quickly sprang to Graham’s defense, with Palin posting this question on her Facebook page: “Are we really so hyper-politically correct that we can’t abide a Christian minister who expresses his views on matters of faith?”

[T]he ceremony’s explicit meaning for the vast population of Christian evangelicals who most value it, inside the military and out, suggests nothing less than a ritual of American Christian nationalism.

One of Graham’s views, as expressed on an ABC program in 2006, is that: “If people think Islam is such a wonderful religion, just go to Saudi Arabia and make it your home. Just live there. If you think Islam is such a wonderful religion, I mean, go and live under the Taliban somewhere.”

And explaining why the Pentagon rescinded the invitation to the observance on May 6, an Army spokesman said: “His past statements are not consistent with the multi-faith emphasis and inclusiveness of this event.”

The spat was just the latest in an on-going fight over prayer day. Last week, a judge from the Western District of Wisconsin struck down the official National Day of Prayer tradition as unconstitutional state-sponsored religious expression—a decision that the Obama administration quickly said it would appeal.

At the heart of the problem is an ecumenical fiction. The National Day of Prayer has always been a ritual of American Christian nationalism, no matter how colorfully varied the vestments of the attendees. Congress established prayer day in 1952, at a time when Americans lived in fear of “atheistic Communism” and nuclear Armageddon. The revelation that the Soviet Union had the bomb, too, had jolted Americans into a millennial religious fervor, comparable to previous “great awakenings.”

Within days of the news about the Soviet bomb, a young sawdust-trail preacher pitched his tent in Los Angeles for a revival meeting and hundreds of thousands of people showed up. “God is giving us a desperate choice,” the preacher railed, “The world is divided into two camps. On one side we see Communism [which] has declared war against God, Christ, against the Bible, and against all religion … Unless the Western world has an old fashioned revival, we cannot last.”

That preacher, of course, was Billy Graham, the father of Franklin Graham, whose patrimony is a gift for God-sanctioned good-versus-evil demonizing, with America certain of its place beside the angels. It is not incidental to this entire story that the Graham enterprise, from that fevered beginning, is called a “Crusade.”

Dean Acheson, describing his view in that period, wrote in his memoir that the threat from Moscow-sponsored Communism “seemed to me singularly like that which Islam had posed centuries before, with its combination of ideological zeal and fighting power.” As was true with the anti-Islamic Crusade in 1096, the response required now had to be rooted in militant Christianity. Hence the unprecedented intrusions into the American public realm of overtly religious expressions, like the National Prayer Day in 1952, the addition of “under God” to the Pledge of Allegiance in 1954, the adoption of “In God We Trust” as a national motto in 1956 and the elevation of Billy Graham to a kind of American Pope.

American Christian nationalism was born again during the born-again George W. Bush administration, with the word “crusade” finding its way back into the presidential lexicon along with “wicked,” and “evil.” In the War on Terror, Bush said, “God is not neutral.” Bush is gone now. But religious militancy persists, both inside and outside the Pentagon.

Of course, the Pentagon is just one of many governmental institutions that observe prayer day. But as last year’s revelation that war briefings had carried Biblical verses on their covers showed, mixing proselytizing with the chain-of-command and the culture of warriors raises special problems. So do commanders’ widespread use of Jesus as morale-booster-in-chief, and the tendency of many in the Pentagon itself to attach Christian references to the War on Terror.

The evangelicals and atheists agree on one thing: The National Day of Prayer matters—especially when its sanctuary is in the Pentagon. Although Graham was eventually disinvited from the event, President Obama has shown that he picks his fights carefully, and it’s unlikely that he will take on the prayer lobby. Obama’s move to appease the devout by appealing last week’s court ruling shows that he has bigger fish to fry. Speaking of fish, it is a symbol of Jesus, and can be seen all across the DoD parking lots.

James Carroll's recent book is Practicing Catholic, a story of American belief. He is a columnist for the Boston Globe and Distinguished-Scholar-in-Residence at Suffolk University. His other books include An American Requiem, which won the National Book Award, House of War, winner of the PEN-Galbraith Award, and Constantine's Sword, now an acclaimed documentary.