The disclosure that there were nearly two years of secret talks between Syrian and Israeli interlocutors is not in itself that historic. Successive prime ministers in the 1990s, after all, pursued the diplomatic track with Damascus - and much more officially. Moreover, Alon Liel himself told Ha'aretz that such unofficial meetings had been fairly common and that there had been "no official Israeli connection" to the talks.
But it is a sharp reminder of the possibilities such negotiations might hold out if they succeeded, not only for Israel but in the wider region.
Whether or not one Ha'aretz source is right in suggesting that having concluded such a deal, Syria would help to broker a peace between Sunni and Shia insurgents in Iraq, there is less doubt that it might at least offer the chance of helping to neutralise Hizbollah - and conceivably the most heavily "rejectionist" Palestinian elements as well.
The strong implication that Syria was keen to take the talks much further will focus renewed interest in the reasons for Mr Olmert's continued refusal to countenance such negotiations until Syria shows, by some tangible concession or sign, that it is ready to modify what Israel sees as its aggressive behaviour in Lebanon or close down the offices of Islamic Jihad or Hamas.
The eminent Israeli analyst Yossi Alpher was quick to point out yesterday that the actual text of the document did not spell out any Syrian commitment on Hizbollah or Hamas. He was also sceptical of how far Ibrahim Suleiman, whom he knows and regards as a "nice guy", could be regarded as a substantive Syrian negotiator.
But he remains strongly in favour of Mr Olmert testing the good faith of the Syrian President and impatient of his failure to tell an evidently very reluctant President Bush that Israel's interests lie in such negotiations. Mr Olmert, after all, told a recent cabinet meeting that talks with Syria would undermine the approach of the US President, who has so far refused to heed calls for any rapprochement with Damascus to get its help in Iraq.
Most Israeli advocates and opponents of talks with Damascus agree Syria is a more dangerous country than it was in the 1990s. But the first group see that as a good reason for attempting negotiations while the second see it as a reason for doing nothing until it changes.
Mr Olmert's political weakness is not conducive to taking political risks. Polls show more than 60 per cent of Israelis in favour of talks, but about the same proportion opposed to giving up the Golan. But the one sure effect of yesterday's disclosures will be to fuel the debate within Israel about whether Mr Olmert should try to bring off the deal with Syria which painfully eluded his 1990s predecessors. Which may just be why the leak occurred in the first place.