Syrian chemical attack: What's the US evidence?

US officials say that soon – perhaps as early as Wednesday – the US will release an intelligence report detailing evidence that Syria used chemical weapons on its own citizens.

“The intelligence community is working on an assessment ... it will come, and I think you can expect it this week,” said White House spokesman Jay Carney on Tuesday.

Mr. Carney and other administration officials say there is “little doubt” that the Syrian regime of Bashar al-Assad is guilty. Given that certainty, what sorts of evidence is the forthcoming intelligence report likely to contain?

For one thing, it’s possible it will reference intercepted communications. Last Wednesday, in the wake of a deadly chemical attack outside Damascus, a Syrian Ministry of Defense official exchanged “panicked” phone calls with the leader of a Syrian Army chemical weapons unit, according to an exclusive dispatch from Foreign Policy Magazine.

The ministry official wanted some answers about what had happened in the nerve agent strike, writes Foreign Policy’s Noah Shachtman.

“Those conversations were overheard by US intelligence services ... and that is the major reason why American officials now say they’re certain that the attacks were the work of the Bashar al-Assad regime – and why the US military is likely to attack that regime in a matter of days,” writes Mr. Shachtman on Foreign Policy’s “The Cable” blog.

The report notes this bit of intelligence raises some questions of responsibility. Was the Army unit freelancing? Was the Ministry of Defense surprised? Did the Syrian military have blanket clearance to use the weapons?

Meanwhile, the British newspaper The Guardian reports that a unit of the Israeli military which specializes in electronic surveillance intercepted a conversation between Syrian officials regarding the use of the chemical weapons.

Israel has provided the US the “bulk” of evidence proving Mr. Assad’s deployment of poison gas, says The Guardian, citing German media sources.

The Wall Street Journal also reports Wednesday that Israel handed the US a key bit of intelligence.

“The intelligence, which the CIA was able to verify, showed that certain types of chemical weapons were moved in advance to the same Damascus suburbs where the attack allegedly took place a week ago,” writes the Journal.

It’s also possible the forthcoming US intelligence analysis will deal with these disclosures only obliquely, or not at all. On Wednesday State Department spokesman Marie Harf cautioned reporters against assuming that signals or human intelligence would be declassified for the effort. 

“We need to protect sources and methods,” said Ms. Harf. 

Beyond this, the US intelligence summary will likely feature evidence provided by local medical personnel as to symptoms of victims, references to the videos of bodies which appear unmarked, and chemical analyses of soil samples from the attack site.

It’s extremely important that the US intelligence community gets its work right, and that the Syria chemical weapons study is accurate, adds Anthony Cordesman, a military expert at the Center for Strategic and International Studies in Washington.

Ten years ago, US intelligence estimates of Iraqi leader Saddam Hussein’s weapons of mass destruction turned out to be wildly off the mark. On Feb. 5, 2003, then-Secretary of State Colin Powell made a presentation to the UN on this evidence that turned out to be “almost totally false”, writes Dr. Cordesman.

This greatly undercut US credibility in the Arab world – indeed, in the world at large. That makes the stakes all the higher for the forthcoming Syrian report.

“It will either redeem the reputation of the US government and US intelligence community or undermine it in ways that make take decades to recover from. Every error, every overstatement of fact ... that does not prove out over time, will impact on US credibility indefinitely into the future,” according to Cordesman.