How Obama knew the Syrian military hadn't used sarin gas in 2013

The following is from Mark Karlin's interview of Seymour Hersh, published yesterday by Truth Out to help publicize Hersh's new book, The Killing of Osama bin Laden. Hersh's remarks in the last paragraph about joint U.S.-Israeli military intelligence monitoring are the jaw-dropper:

Your book explores the infamous sarin attack that almost led to wholesale US military involvement in the intractable Syrian deadly scrum. What was wrong with the official US version concerning the perpetrators of the August 21, 2013, use of chemical weapons in Syria?

 The critical issue [regarding] the August 20, 2013, sarin attack in a suburb of Damascus is that the US and its allies knew from highly classified CIA and allied intelligence reporting throughout the spring and summer of 2013, that the jihadist opposition to Assad (primarily al-Nusra) had the ability to manufacture a crude form of sarin and other gas warfare items. And yet, in the days after the August gas attack, the Obama administration focused its attention solely on the fact that the Syrian army was known to have a significant chemical warfare (CW) capability. The Syrian government became the only suspect, at a time when there were, at the minimum, two suspects. That was a fatal flaw. It also is so that the Syrian gas arsenal was not a secret, as many in the US insisted, but widely known for decades to exist.

The CW system had been generated by Bashar’s father, Hafez al-Assad, who ran the nation for 20 years, as a deterrent to the known -- if undeclared -- Israeli nuclear arsenal. But the fact that Syria had a weapons capability did little to change the reality that Israeli nuclear weapons clearly would be dominant in any war. The Syrian system was seen after Hafez’s death in 2000, with young Bashar al-Assad now in charge, to be useless, expensive, and hard to maintain -- and publicly complained about as such. I, in The New Yorker magazine, as had others, had written about the Syrian CW arsenal after the 9/11 attacks.

There was another consideration: Israel and the US had joined forces, initially in secret, to monitor all of the suspected CW storage depots scattered through Syria; there were more than 20 of them. Any effort to begin preparing for a CW warfare attack would immediately trigger alarms in the US and Israel, and the government in Tel Aviv would begin preparing for a pre-emptive air force attack. The joint US-Israeli system did not signal an alarm in the hours before or after the CW attack near Damascus -- clear evidence that the attack could not have come from a Syrian CW facility. To this date, despite constant references by the media to the Syrian attack, there has been no specific evidence linking the Syrian version of sarin, whose sophisticated additives and chemical make-up is known to the West, to the far cruder sarin found at the site.

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