The connection between Osama bin Laden and Abu Musab al-Zarqawi was cemented with Mr. bin Laden's latest taped statement on Tuesday, in which he praised the Jordanian militant and said anyone who participates in Iraq's Jan. 30 election will be considered an infidel and fair game for attack.
When Mr. Zarqawi's terrorist movement emerged in Iraq more than a year ago, intelligence analysts saw it as separate from Al Qaeda, with more ferocious rhetoric than the better-known terror group and a willingness to kill large numbers of Muslim civilians.
But now, the US and its allies face a grave and growing threat: an alliance of mutual interests and convenience between the group that carried out the 9/11 attacks in the United States and the one that has contributed so much to Iraq's chaos.
"There were certainly some differences between bin Laden and Zarqawi,'' says Rohan Gunaratna, a terrorism expert at Singapore's Institute of Defense and Strategic Studies. "But these differences were minor compared to the biggest things they have in common - their desire to hit at the US."
Mr. bin Laden's statement coincided with a devastating spurt of insurgent activity inside Iraq. On Tuesday, insurgent attacks killed at least 54 people in the center of Iraq, including the detonation of a massive bomb in a house police were searching in Baghdad that killed at least 29, and 12 policemen who were captured and killed.
Wednesday the Assar al-Sunnah Army, the insurgent group that claimed responsibility for the Dec. 21 bombing of the US base in Mosul, signaled it would escalate attacks in the coming days by calling for a three-day "curfew" for civilians. In the statement, reported by the Associated Press, the group said, "All polling stations and those in them will be targets for our brave soldiers."
US and Iraqi officials concede that violence is likely to continue to grow as the elections draw nearer, but add they are determined to hold the elections on schedule, a plan which both bin Laden and Zarqawi are intent on disrupting.
For bin Laden, the advantages of the alliance are clear, says Mr. Gunaratna. The operational capabilities of Al Qaeda have been relentlessly trimmed back by the US since the attacks on Sept. 11, 2001, but he and most of his ideological core remain free.
Since the Iraq invasion, bin Laden has repeatedly called Iraq a battleground against the "crusader" West, even as Zarqawi has emerged as his principal agent. Zarqawi has positioned himself at the head of a growing network that US officials believe has been behind more than 70 car-bombings inside Iraq and "now makes him the de facto operational head of the Al Qaeda movement, not the Al Qaeda group, worldwide,'' says Gunaratna.
Zarqawi and his fighters were the target of the US siege on Fallujah last month. But US officials say they suspect many of the militants escaped Fallujah to other Sunni cities such as Mosul, which has been the scene of recent insurgent attacks.
By combining their resources, Zarqawi and Al Qaeda seem to be aiming to further amplify their message of total war against the US, the Middle Eastern regimes it favors, and Israel, with an expanded Internet reach and ongoing attacks against US and Iraqi forces.
Bin Laden's latest statement urged Muslims to attack the US and any Iraqis that work with the interim arrangements, including voters and election workers. In the two-minute, five-second audio tape, he referred to what he sees as "the third world war," led by the "Crusader Zionist Alliance" against Muslims who, in turn, "have a rare and precious opportunity to get out of the dependency and slavery to the West."
Zarqawi originally called his group Tawhid and Jihad, and his first statement of note in Iraq was peppered with venomous anti-Shiite attacks. Analysts once thought Bin Laden was unwilling to call for all out war between Shiite Muslims and Sunni Muslims, the dominant Muslim sect of which both bin Laden and Zarqawi belong.
Both men's Salafy branch of Sunni Islam is highly intolerant of Shiites, as is Saudi Arabia, but it had seemed that bin Laden wanted to keep the focus on the US. Zarqawi, for his part, seemed to want to form his own organization.
But in an October Internet statement, Zarqawi announced he was changing the name of his group to "Al Qaeda in the Land of the Two Rivers,'' a reference to the Tigris and Euphrates. In Tuesday's tape bin Laden called Zarqawi his organization's "emir," or leader, in Iraq.
In bin Laden's other recent statements before this one, he sought to speak to Americans in a language of justice and democracy - a departure from his usually more religious and militant approach. Some analysts thought it was a sign that bin Laden was seeking not only to influence the US election, but to broaden his appeal among Muslims turned off by his earlier virulent words and actions.
While his latest tape may be a return to form, it doesn't mean that he's abandoning his attempt to influence politics. "Bin Laden needs to be understood as a crafty politician, a rational actor who tailors his comments to different audiences,'' says Toby Jones, a Saudi Arabia specialist for the International Crisis Group based in Cairo. "Perhaps different statements are designed for different publics, so he doesn't worry too much about consistency."
What's clearer is that bin Laden feels in a safe enough position, making three statements in two months after years or scarce public statements.
Islamist terror groups have been increasing in size and number inside Iraq since the US invasion in April 2003. While Zarqawi's group is the best known, the Ansar al-Sunnah, which has grown strong in the area around Iraq's third largest city of Mosul has also become a major player, carrying out assassinations of Iraqi police, politicians, and construction workers.
The group claimed responsibility for the infiltration of a suicide bomber into a US military base last week who killed 19 Americans and five Iraqis. It posted a video of a man it said was the bomber on its website, wearing an explosives belt and preparing to die. The attack was the largest loss of US life in a single incident since the war began.
"There's no doubt that Iraq has become a major battleground for the global jihad movement, which is composed of many different autonomous groups of which Al Qaeda is but one component,'' says M.J. Gohel, director of the Asia Pacific Foundation, a security think tank in London.
"Iraq is one place in the planet where they can hit very directly at US interests and with much tragic success, so naturally bin Laden wants a piece of the action. He's happy to give his blessings to [Zarqawi], who has operational capabilities in Iraq that Al Qaeda doesn't have, and expand his franchise in this way,'' says Mr. Gohel.
Gunaratna expects that the role of Islamist fighters, both foreign and local, will continue to rise in Iraq in the years ahead, mirroring the evolution of the Soviet war in Afghanistan in the 1980s. In the first few years of the conflict, there was only a trickle of foreign fighters into Afghanistan, but that accelerated as the war dragged on.
He says that more and more Muslims from the Middle East and Europe are seeking to fight in Iraq, and that Al Qaeda is seeking to position itself to integrate these fighters into its broader vision of a jihad against all American interests, not simply limited to the specifics of Iraq.
"One of the overarching trends of Al Qaeda's strategy has been to co-opt like-minded groups that start out with local interests in mind and seduce them into waging global jihad,'' says Gunaratna.
"In some ways Al Qaeda as an organization is dying, but it is influencing other groups to become like Al Qaeda. Iraq is now the major recruiting center," he says.
He also worries of another trend that may mirror the Afghan experience. "These fighters have been practicing terrorist tactics, car-bombings, in Iraq from day one and now they're much more radicalized. They'll take their tactics home with them when they leave."