On the eve of the U.S. invasion of Iraq in 2003, a 36-year-old Jordanian who called himself "the Stranger" slipped into the suburbs of Baghdad armed with a few weapons, bags of cash and an audacious plan for starting a war he hoped would unite Sunni Muslims across the Middle East.
The tattooed ex-convict and high school dropout had few followers and scant ties to the local population. Yet, the Stranger — soon to be known widely as Abu Musab al-Zarqawi — quickly rallied thousands of Iraqis and foreign fighters to his cause. He launched spectacular suicide bombings and gruesome executions targeting Americans, Shiites and others he saw as obstacles to his vision for a Sunni caliphate stretching from Syria to the Persian Gulf.
Zarqawi was killed in a U.S. air strike in 2006, but the organization he founded is again on the march. In just a week, his group — formerly known as al-Qaida in Iraq and now called the Islamic State of Iraq and Syria, or ISIS — has seized cities and towns across western and northern Iraq at a pace that might have astonished Zarqawi himself. Already in control of large swaths of eastern Syria, the group's black-clad warriors appear to have taken a leap toward realizing Zarqawi's dream.
It's unclear whether the gains of ISIS will last, or whether the Sunni tribesmen who apparently aided the jihadists will submit to living under the group's harsh brand of Islamic law.
Counterterrorism officials who tried to defeat the group during the Zarqawi era expressed begrudging respect for the ability of ISIS to recover from virtual extinction in the years after his death. The current leader, a former Iraqi teacher known as Abu Bakr al-Baghdadi, managed to find new purpose in the Syrian conflict and renewed strength in the lawless regions of eastern Syria and western Iraq, where his fighters could train and plan without interference from U.S. and Western military forces.
A senior Middle Eastern intelligence official who has closely tracked the fast-moving developments in Iraq said the astonishing recent gains of ISIS were mostly due to skillfully forged alliances with Sunni tribal leaders.
ISIS and the tribal leaders share a hatred for the ruling regime dominated by Shiites, said the official, who spoke to the Washington Post on condition that his name and nationality not be revealed in discussing his country's intelligence assessments.
So far, at least, ISIS has managed to avoid alienating its natural Sunni allies the way Zarqawi did. The Jordanian's indiscriminate and brutal attacks on Iraqi civilians helped give rise to the Sunni backlash known as the Anbar Awakening, in which tribal sheiks withdrew their support from Zarqawi and helped U.S. forces find and destroy his operatives.