(Analyst's note:  Absolutely must read.)

IBD Special Series:
Jihadist 5th Column: Part 1 | Part 2 | Part 3

The internal threat from Muslim extremists in the military extends to high-level Defense Department aides who have undermined military policy. In fact, one top Muslim adviser pushed out an intelligence analyst who warned of the sudden jihad syndrome that led to the Fort Hood terrorist attack.

An honored guest of the Ramadan dinner at the Pentagon this September was Hesham Islam, who infiltrated the highest echelons of the Ring despite proven ties to U.S. terror front groups and a shady past in his native Egypt.

As senior adviser for international affairs to former deputy Defense Secretary Gordon England, Islam ran interference for the Islamic Society of North America and other radical fronts for the Egypt-based Muslim Brotherhood, the subject of my new book "Muslim Mafia."

For example, Islam persuaded brass to sack a Pentagon analyst, Stephen Coughlin, after he advised cutting off outreach to ISNA, which he accurately ID'd as part of a covert terror-support network in the U.S. — something the Justice Department recently confirmed in a major terror finance trial.

Islam invited ISNA officials to lunch with the avuncular England, known by insiders as Gullible Gordon, who in turn spoke at ISNA confabs. Islam also helped set up a Pentagon job booth at one recent ISNA convention to recruit Muslim chaplains and linguists.

Most disturbing, Islam met regularly with Saudi and other embassy officials lobbying for the release and repatriation of their citizens held at Gitmo. He in turn advised England, who authorized the release of dozens of Gitmo detainees. Some have resumed terrorist activities.

No one really knew who Islam was when he was promoted — in fact, the Pentagon removed his bio from its Web site after reporters noted major inconsistencies in it — yet he was allowed to get inside the office of the Pentagon's No. 2 official.

"In effect," a senior U.S. Army intelligence official told me, "we've got terrorist supporters calling the shots on our policies toward Muslims from the highest levels."

Meanwhile, politically incorrect prophets like Coughlin have been frozen out. After the betrayal at Fort Hood, the military could use his analysis of Islamic doctrine more than ever.

I attended a private briefing by Coughlin in February. In a PowerPoint presentation, he detailed how jihadists use the Quran to justify their actions. Some of his slides matched almost word-for-word Hasan's own PowerPoint slides extolling the virtues of jihad and martyrdom. Both, for instance, quoted from the same Quranic passage known as the "Verse of the Sword."

Eerily, Coughlin predicted Hasan's mind-set. He first began briefing the Pentagon on this jihadist doctrine in 2002. So brass can't say they didn't know.

They were warned that the enemy was drawing on religious principles, and that our own Muslim soldiers could succumb to such thinking.

And they were warned that by using ISNA and other radical Brotherhood fronts to endorse Muslim chaplains and recruit Muslim soldiers, they were courting enemies of the U.S. — and courting disaster. But they were too drunk with political correctness to listen.

The jihadist threat to U.S.-based armed forces is external as well as internal — and far greater than reported. It comes from both inside and outside the military.

Fort Hood follows in a line of attacks or plots against military personnel and installations since 2006, when al-Qaida spokesman Adam Gadahn, an American convert to Islam, appeared in a video with Osama bin Laden and encouraged fellow Muslim-Americans to "go on a shooting spree at the Marines' housing facilities at Camp Pendleton" in California.

Over the past few years, an alarming number of homegrown Muslim terrorists have targeted military installations, including:

• A North Carolina cell of white converts to Islam who trained to attack Marine headquarters in Quantico, Va.

• A New York cell of black jailhouse converts who planned to down planes at an Air National Guard base with shoulder-fired missiles.

• A lone Muslim convert who shot two soldiers at a Little Rock, Ark., Army recruiting station, killing one.

• A Los Angeles cell of black Muslim converts who plotted to hit military bases in California.

• A New Jersey cell of hardened jihadists who trained to attack Fort Dix by posing as pizza delivery drivers.

The Fort Dix terrorists had also talked about joining the U.S. Army so they could kill U.S soldiers from the "inside." They planned to hit the post just days after a National Guard unit arrived back from Gitmo. Some of them were inspired by al-Qaida preacher Anwar Awlaki, who on his Yemen-based Web site calls for jihad against U.S. military targets inside and outside the U.S.

But so do so-called moderate American clerics like Zaid Shakir. In "Muslim Mafia," I transcribe for readers a CD recording of one of his sermons circulating in mosques across America. In it, he exhorts the Muslim faithful to attack planes carrying the 82nd Airborne.

Frequently booked by the Council on American-Islamic Relations (CAIR) as a guest speaker at its events, Shakir tells his Muslim audience: "Jihad is physically fighting the enemies of Islam to protect and advance the religion of Islam. This is jihad."

Acceptable targets of jihad, he says, include U.S. military aircraft. "Islam doesn't permit us to hijack airplanes filled with civilian people," he said, but "if you hijack an airplane filled with the 82nd Airborne, that's something else."

The 82nd Airborne is based out of Fort Bragg, which is part of North Carolina state Sen. Larry Shaw's home district. Shaw is CAIR's new chairman. He is also a minority contractor who operates Shaw Food Services Co. near Fort Bragg. According to the legislator's financial disclosure form, Shaw Food customers include the Defense Department.

Yet CAIR, like ISNA, is an unindicted terrorist co-conspirator. The FBI says CAIR is a terrorist front group and has cut off formal ties to it. So should the military.

Will Fort Bragg be next? Does anybody care?

This enemy is hiding behind a religion, making it easier for them to infiltrate our sensitive security agencies. Communist spooks did not have such an advantage.

As the wars in Afghanistan and Iraq drag on, and as long as our troops are deployed in those Muslim countries, our troops stationed here will increasingly be targeted by homegrown jihadists.

To protect them, military command must stop currying favor with suspect Muslim groups and start beefing up counterintelligence activities. It must institute a policy of zero tolerance for Jihad Joes in the ranks.

At Fort Hood, the military's PC mind-set led to a horrific failure in intelligence and force protection. Commanders missed clear signs that an Islamic fanatic harboring deep-seated resentment against the U.S. had infiltrated their officer corps. They were too busy trying to win Muslim "hearts and minds." We saw how well that worked on Hasan.

If Fort Hood did not open their eyes, snap them out of their PC slumber, nothing will. Our brave men and women in uniform already have to worry about getting ambushed in Iraq and Afghanistan. They shouldn't have to worry about getting ambushed at home.

One unnamed Army chaplain confided to McClatchy Newspapers that more than a few Muslims are conflicted about honoring their duty while fighting other Muslims. What other Muslim soldiers are betraying their oath, betraying their security clearance, betraying their country?

While there is rightly placed concern that we not label all Muslims as Islamic terrorists or enemy sympathizers, it is entirely proper to address certain aspects of violence as uniquely Islamic. After all, our enemies cite the sources of Islam as the foundation of their global jihad.

By ignoring this demonstrably obvious fact, the military is violating the first rule of war: Know thy enemy and what motivates it. That's a recipe for defeat.

• Sperry, a Hoover Institution media fellow and former IBD Washington bureau chief, is the author of "Infiltration" and the new book "Muslim Mafia."