In among the retrospectives and tributes timed for next week's 20th anniversary of the assassination of Yitzhak Rabin, there's a rather remarkable hour-long edition of the much-admired This American Life podcast. Despite the name, this programme focuses not on the US, but on Israel - and on one curious aspect of the fallout from that terrible day in November 1995 when a Jewish ultra-nationalist gunned down the only Israeli leader who has genuinely seemed both willing and able to solve the apparently endless conflict with the Palestinians.

It's become commonplace to compare Rabin's murder with the Kennedy assassination 32 years earlier - the shock, the public grieving, the candlelit vigils - but one aspect comes as a surprise. In Israel, there is a cottage industry of JFK-style conspiracy theories about the murder, claiming among other things that Yigal Amir fired blanks and that Rabin wanted to stage his own death to discredit the Israeli right. Even Rabin's own daughter was sufficiently puzzled by a hole on the front of her father's bloody shirt - odd, because Amir shot him in the back - that she handed the garment over to the programme's reporter for forensic testing in the US. (It turned out not to be a bullet-hole at all.)

I listened to all this intrigued, of course, but also with a sense of great sadness. It struck me that these theories - all of them absurd, on a moment's reflection - were not really about the mechanics of the 1995 shooting at all. They were instead the signs of a society that can't accept what happened 20 years ago, that on some level still refuses to believe it.

And who can blame Israel if that's so? For Yigal Amir was surely the most effective assassin in modern history. He wanted to destroy the peace process, then real and under way, and he did so. Oslo is a dead letter. The peace camp, as it used to be called, has shrunk with each passing year. Once mainstream, it is now confined to the margins. Of the 20 years since Rabin's murder, Rabin's Labour party has ruled for just over two. The dominant figure has been Benjamin Netanyahu, who Rabin's own widow always blamed for breathing oxygen into the ultra-right fire that eventually devoured her husband, and who will soon be the longest-ruling premier in the country's history.

It means that Israel is still paying the price for that killing. It has been left with a leader who is utterly visionless, a fact captured exquisitely by that photograph of him surveying the landscape with a pair of binoculars, the lenses still covered by rubber caps. A leader who has breezily ruled out the two-state solution, even though that path remains the only way out for a country faced with a future as either an apartheid state or a binational entity fated to never-ending inter-ethnic violence, of the kind so gruesomely previewed in the last few weeks of stabbings and shootings.

Israelis know a lot more than a man was shot that night

Before Rabin's death, a different kind of future seemed to beckon for Israel. Surely peace would come, just as it did in the 1990s for South Africa and Northern Ireland. Israel would come in from the cold. The two peoples would live side by side. Anything was possible. But once Rabin was gone, all that seemed like so much naivety. Today, Israel is isolated, shunned as a pariah this very week by legions of advert-signing academics. Tempting to dismiss such gestures, perhaps, but they might be a harbinger of the international isolation that is on its way.

So I understand why Israelis might lap up theories that say it wasn't so. They know that a lot more than one man was gunned down that bitter November night.

Jonathan Freedland is executive editor of the Guardian