An impersonator who looks like the country's leader murders him, takes his place, and thereafter deliberately leads the state to defeat and catastrophe. That was the plot of a Hollywood film I saw long ago.
Sometimes it is almost tempting to think up some such tale to account for Israel's behaviour - to conclude that a bitter enemy of the Jewish state and of its best immediate and long-term interests has somehow got control in Jerusalem and works relentlessly to undermine Israel.
The self-righteous but too often senseless eternal prattle about "terrorists" with which the Israeli governments respond to criticisms only adds an extra element of repulsiveness to Israel's treatment of the Palestinians.
The flotilla of relief ships which the Israeli army bloodily attacked in international waters was far more a political demonstration against the Israeli blockade of Gaza than an attempt to bring practical relief to Gaza.
The quantity of relief goods it carried was comparatively insignificant in proportion to the needs of the people of Gaza, and at best would have brought a marginal amelioration. Primarily it was a political demonstration of solidarity with the people of Gaza and condemnation of Israel.
The Israeli army's attack on the ships turned the flotilla into a tremendously effective political demonstration against Israel. If that had been the intention, then the Israeli authorities would have succeeded brilliantly. They could not have done more if that had been their intention.
The Israeli army treated the people on the Mavi Marmara with the grotesquely disproportionate lack of restraint with which they habitually treat the Palestinians. The political message of the organisers of the flotilla was made to reverberate like thunder round the world.
None of the Israeli explanations stand up. So, the Israeli soldiers coming down ropes from helicopters were attacked with sticks - or iron bars, knives, whatever - by Islamist militants on the ship, some of whom at least will have advocated the destruction and abolition of the Jewish state by Arab military action?
So? That was not predictable, even as a contingency? That attempt to defend the ship from airborne attack justified the lethal response of armed professional soldiers, the killing of nine and the wounding of at least 30?
Only in the eyes of people who accept no restraint and no limits, people grown used to the exercise of lethal and disproportionate force, justified with the conventional cant against terrorists.
So soldiers do not, by the nature of their trade, make gentle and restrained policemen? That was not known, not to be expected?
Israeli soldiers captured most of the ships in the flotilla without bloodshed, therefore what happened on the sixth was not the fault of the Israeli army? That is only a variant on the argument that any resistance justifies massively disproportionate response.
The cry of Israeli prime minister Binyamin Netanyahu that the occupants of the Mavi Marmara were "terrorists" is as if designed to discredit what Israel says when it is a matter of real terrorists.
What happened on the ships follows from the overall policy of recent Israeli governments: the fact that most Israeli leaders pay only, at best, lip service to the policy of allowing the Palestinians to set up an independent state, alongside Israel, in the Occupied Territories and Gaza. That policy is the only just solution to the Israeli-Palestinian conflict.
Something much better than the Israeli policy that led to the shipboard slaughter, to the Israeli blockade of Hamas-ruled Gaza, and to all the many disproportionate and bloody incidents in the Occupied Territories is, probably, available at will to an Israel acting from its present strength.
The present Israeli government, despite occasional words to placate Washington, is opposed to any just two-states solution. There is opposition within Israel to the government's policy, but Israel will not, it seems, change until it is forced to do so by Washington and the EU.
Will the massacre on the Mavi Marmara and the outcry against Israel lead to the deployment of enough pressure on Israel, and, in the most important place, to US pressure to end the blockade of Gaza? If it does, then those responsible for what happened on the ship will, inadvertently, have served the cause of progress and humanity.