Here's an unofficial translation of a Project Harmony document (thank you Powerline) on the flow of truck traffic from Iraq into Syria prior to the March 2003 invasion. No one knows with any certainty what was in the trucks, but it’s been pretty well established that there was a heavy traffic flow from Iraq into Syria before and immediately after the invasion commenced. On page 84 of his book, Fiasco, Tom Ricks notes that:

Baathists and intelligence officials [were able] to flee to the sanctuary of Syria, taking money, weapons, and records with them with which to establish a safe headquarters for the insurgency that would emerge that summer. Some of this movement occurred before the war began, when, according to retired Air Force Lt. Gen. James Clapper, the head of the U.S. National Imagery and Mapping Agency, satellite imagery showed a heavy flow of traffic from Iraq into Syria.

On October 28, 2003, Agence France Presse reported:

The director of a Pentagon agency that analyzes imagery from satellites and spy planes said Tuesday Iraqi leaders may have moved weapons of mass destruction "material" into neighboring Syria before the war.

Retired Lieutenant General James Clapper said senior Iraqi leaders made an intensive effort to bury, hide and disperse equipment, documents and other material related to their weapons of mass destruction programs in the months before the war, moving some of it out of the country.

"I think personally that the senior leadership saw what was coming and I think they went to some extraordinary lengths to dispose of the evidence," he said, director of the National Imagery and Mapping Agency. "I'll call it an educated hunch."

He noted there was an "uptick" in truck traffic from Iraq into Syria before the onset of combat and even as the war was raging.

Clapper, a former director of the Defense Intelligence Agency, acknowledged that there were limits to what overhead surveillance can detect inside trucks.

"But certainly, inferentially, the obvious conclusion one draws is that the certain uptick in traffic ... may have been people leaving the scene, fleeing Iraq, and unquestionably, I am sure, material," he said….

I wonder if Gen. Clapper still holds this view today.