Mr. Assad’s objective: to keep the U.S. occupation off balance by helping al Qaeda kill Americans.
But Mr. Assad’s move also enabled al Qaeda to set up a logistics foothold in Syria that now is being used against him.
The al Qaeda-linked Al Nusra Front is conducting war on the Assad regime with a band of about 6,000 fighters established by jihadists in January 2012. It wants Mr. Assad to be replaced by a Sunni Islamic state.
Al Nusra knows how to move men and arms inside Syria to the point where, analysts say, they have become the most deadly force among a hodgepodge of opposition groups.
“Al Qaeda fighters who are back in Syria, I am confident, they are relying on much they learned in moving through Syria into Iraq for more than five years when they were waging war against the U.S. and Iraq Security Assistance Force,” said retired Army Gen. John M. Keane, an adviser to commanders in Iraq.
In fact, al Qaeda kept alive its networks in Syria, according to the Combating Terrorism Center at West Point, N.Y., which advises Washington policymakers. It notes in a May 2012 report, as jihadists streamed into Syria, “Al Qaeda has an active affiliate in neighboring Iraq that has long-standing logistical capabilities in Syria.”
More than any other Middle Eastern leader, it was Mr. Assad who bolstered al Qaeda’s ranks in Iraq. He let fighters use his country as a platform to jump into Iraq, where they learned how to inflict mass killings of civilians and ambush U.S. and Iraqi troops — skills used today against Syria’s regime.
Thousands of al Qaeda recruits moved through Syria into Iraq in the mid- to late 2000s, said a former military intelligence official who requested anonymity because he is not authorized to discuss what he did in Iraq. In some instances, the U.S. intercepted 10 to 20 in one group trying to make their way to the homes of a network commander.
“Inside Syria, they moved from safe house to safe house,” the former official said. “They crossed the border at check stations where they had sympathizers or paid off dirty guards.”
Gen. Keane said U.S. joint intelligence/special operations units became so adept at finding and killing al Qaeda that headquarters in Pakistan shut off the flow.
Now, however, with U.S. troops gone and Iraqi counterterrorism not on a par with that of the Americans, al Qaeda has rebuilt networks, freed some fighters from prison and sent manpower to the Al Nusra Front.