In appearances across the US, President Bush has been campaigning against withdrawing troops from Iraq, arguing that to leave now would hand a historic victory to Al Qaeda and inspire new generations of jihadists to attack the US.

But a letter that has been translated and released by the US military indicates that Al Qaeda itself sees the continued American presence in Iraq as a boon for the terror network, which has recently shown signs of expanding into the Palestinian territories and North Africa.

"The most important thing is that the jihad continues with steadfastness ... indeed, prolonging the war is in our interest," says the writer, who goes by the name Atiyah. The letter, released last week, was recovered in the rubble of the Iraqi house where Abu Musab al-Zarqawi, former leader of Al Qaeda in Iraq, was killed by a US bomb in June.

If the letter is accurate, it provides a window into the group's strategic thinking on Iraq that differs starkly from the one the Bush administration has been expressing publicly – a view the president reiterated Wednesday when he said that Al Qaeda believes that "America is weak, and if they can kill enough innocent people we'll retreat. That's precisely what they want."

While the letter was released only recently, Atiyah, thought to be a senior Al Qaeda leader whose full name Atiyah Abd al-Rahman, apparently wrote it last December from the Pakistani region of Waziristan. It has surfaced among a flurry of other communiqués from Al Qaeda.

Al Qaeda's No. 2, Ayman al-Zawahiri, released a videotape this week in which he lashed out at Mr. Bush and Pope Benedict XVI. On Sept. 28, Abu Hamza al-Muhajir, believed to have replaced Mr. Zarqawi as the leader of Al Qaeda in Iraq, published an Internet statement in which he reached out to Sunni tribal leaders who have been in conflict with Al Qaeda. And a new group claiming to be Al Qaeda in Palestine issued a video attacking Palestinian political leaders.

But the Atiyah letter, reflecting as it does the candid opinions of Al Qaeda, rather than the group's propaganda statement crafted for public consumption, appears to offer the most insight. It is largely focused on the fact that Zarqawi's tactics were alienating Iraqi Sunni leaders, and urges him to move with more caution.

He strongly warned Zarqawi against assassinating Sunni leaders. Al Qaeda is a Sunni organization that has been trying to use minority Sunni anxiety in Iraq to build support. The letter also called the Zarqawi-organized bombing of three hotels in Jordan in 2005 a "mistake," arguing that expanding Iraq's jihad beyond its borders too soon will cost them public support.

At one point, Atiyah muses that perhaps Zarqawi should step down from his leadership role, "if you find at some point someone who is better and more suitable than you." Since Zarqawi's death, a "more suitable" figure from Al Qaeda's standpoint has indeed emerged.

"In order to understand this letter one has to see the circumstances of when this letter was released,'' says Rita Katz, the director of the SITE Institute, which is devoted to tracking Islamist militant groups. "This followed after Zarqawi had an audio message ... in which he threatened the tribes of the Sunnis who wouldn't cooperate with him. That was a real turning point.

"The letter from Atiyah is basically his response to this. He's telling him that instead of fighting Sunni opponents, you should reach out with more peaceful solutions."

Ms. Katz says Mr. Muhajir's Sept. 28 statement shows he has taken that advice to heart. She points out that a number of Sunni tribes in Iraq's turbulent Anbar Province have turned against Al Qaeda's main umbrella group in Iraq, the Mujahideen Shura Council (MSC), in recent months.

"Al-Muhajir's latest speech was quite interesting, because he basically said sorry to the heads of the Sunni tribes. 'We need you. We'll work together to defeat the enemy.' "

The day before his speech, Al Jazeera reported a statement it said was delivered by Ahmad Naji al-Juburi, head of the tribal council in Salahuddin Province north of Baghdad, in which he lashed out at Al Qaeda for killing "civilians, defenseless people, police and security men ... Al Qaeda said it came to Iraq for jihad and to liberate it from occupation [but] what Al Qaeda is doing is utterly at odds with what it announced."

Katz and others say Muhajir is eager to mend fences with Sunni leaders, because he knows that if Al Qaeda loses the support of Sunni tribes, it will be in a very tenuous position.

"Al-Muhajir took another step toward undoing some of the alienation Abu Musab al-Zarqawi had created in Iraq's Sunni community," Michael Scheuer, who ran the CIA's bin Laden unit from 1996 to 1999 and is now a senior fellow at the Jamestown Foundation in Washington wrote in a commentary on Muhajir's and other recent Al Qaeda communications.

How long Muhajir will be in charge of Al Qaeda in Iraq is unclear. Earlier this week, Iraqi National Security Adviser Mowaffak al-Rubaie said security forces are close to catching him. On Sept. 28, the US military caught a man it described as his driver. But given the ease with which Al Qaeda in Iraq weathered the killing of Zarqawi, analysts are skeptical that killing Muhajir will have much impact on Iraq's war.

"When Zarqawi was killed, people said that was the end of the insurgency and the end of the mass killings. But in fact we've seen mass killings increase dramatically since," says Katz. "Al Qaeda in Iraq played an important role at the beginning of the war. Zarqawi set up something that hadn't existed before, but at this stage the infrastructure is set up very nicely."