Inconvenient though it may be, report pinning blame on Syrian opposition for chemical attack is likely true.
Why would anyone believe Seymour Hersh? True, he's the Pulitzer Prize-winning investigative reporter who broke the story of the massacre committed by US Army troops at My Lai in 1968 during the Vietnam War, and revealed the torture and sexual humiliation of Iraqi prisoners by US military police at Abu Ghraib prison in 2004. But he's getting old (77), and he's a freelancer, and he won't even disclose the name of his key informant.
Whereas the US Government has hundreds of thousands of people working for it just gathering and analysing intelligence, and the American media are famed worldwide for their brave defence of the truth no matter what the cost. Besides, has the US Government ever lied to you in the past?
So we obviously should not give much credence to Hersh's most recent story. It alleges that the poison gas attack in Damascus last August that killed more than 1000 people, and almost triggered a massive US air attack on Syria, was not really carried out by Bashar al-Assad's tyrannical regime (which the US wants to overthrow).
It was, Hersh says, a false-flag operation carried out by the rebel al-Nusra Front with the purpose of triggering an American attack on Assad. If you can believe that, you would probably also believe his allegation that it was the Turkish Government, a US ally and Nato member, that gave the jihadi extremists of al-Nusra the chemicals to make sarin (nerve gas) and the training to carry out the mass attack in Damascus.
Hersh even says that it was General Martin Dempsey, the chairman of the US Joint Chiefs of Staff, who told President Barack Obama just days before the American strikes on Syria were due to start that the evidence was not strong enough to justify an American attack on the Syrian regime.
The rest of the story we already know. Obama postponed the attack by deciding, quite suddenly, that he had to get Congressional support for it. Then he cancelled it entirely once the Russians gave him the face-saving alternative of getting Assad to hand over all of his chemical weapons for destruction. There is no chance of an American attack on Syria now. But could Hersh's story be true?
Not one American paper or magazine was willing to print it, so it was finally published in the most recent issue of the London Review of Books. The US media are still studiously ignoring the story, and the Turkish Government and various branches of the US Government have issued indignant denials. But the official story never made any sense at all.
By last August it was clear that Assad's regime would eventually win the civil war unless there was some radical change in the situation (like an American bombing campaign against it).
So Assad's survival depended on not giving the United States any reason to attack him.
Barack Obama had already said that any use of poison gas by the Syrian regime would cross a "red line" and trigger an American attack. In mid-August there were United Nations inspectors in Damascus to look into two much smaller attacks earlier in 2013 that seemed to involve poison gas. And we are asked to believe that at that precise moment Assad thought it would be a neat idea to kill one or two thousand innocent civilians in the city with poison gas.
So who did it? The obvious question to ask was, who stands to benefit from this attack? The answer was certainly not Assad. Being wicked does not make you stupid. Whereas the rebels had every reason to do it, in order to suck American firepower in on their side.
Recep Tayyip Erdogan, Turkey's Prime Minister for the past 11 years, has backed the Islamist rebels in the Syrian civil war from the start, and he will be in deep trouble if they lose. They will lose, unless Turkey or the US comes to their aid militarily. Erdogan would obviously have the US Air Force do it rather than his own armed forces. So he had a good motive for giving the rebels the poison gas.
Hersh says he has been told by a former senior official in the US Defence Intelligence Agency that that is what happened. You can read the details on the website of the London Review of Books. And yes, he's old, but that just means he has been getting it right about a lot of different things for a long time.
He's just a freelancer, but that's why people with a whistle to blow trust him to get the story out. And no, he hasn't got confirmation from three separate named sources. That's not how whistle-blowing works. But he is Seymour Hersh, and I strongly suspect that he is right.
Gwynne Dyer is an independent journalist whose articles are published in 45 countries.