Days before he sets out on an intensive effort to reach a peace treaty with Syria, Israel's Prime Minister, Mr Ehud Barak, has been reminded of the fragility of his governing coalition.
Next Monday Mr Barak is to travel to Shepherdstown, Virginia to open at least 10 days of negotiations with the Syrian Foreign Minister, Mr Farouq a Sharaa, in the most serious effort yet to end a half-century of hostility.
But rather than prepare for the talks, Mr Barak has to concentrate all his skills on keeping his multi-party coalition together, after Shas, the ultra-Orthodox faction that is one of his key allies, yesterday threatened to bolt.
Without Shas, which has 17 members in the 120-seat Knesset, Mr Barak would be hard-pressed to maintain his parliamentary majority and, theoretically at least, his government could fall in a vote on the state budget which has to be held by the end of the year.
The dispute with Shas, however, has nothing whatever to do with the Syrian peace talks.
On that issue, the party is backing Mr Barak. Shas's spiritual leader, a renowned Torah scholar named Rabbi Ovadya Yosef, has ruled in the past that Jewish law obliges Israel to give up occupied land, if such a policy will save lives.
Rather, the Shas threat to defect to the opposition benches stems from Mr Barak's refusal, thus far, to allocate some $25 million of government funds to cover a deficit in the Shas school system - a network of ultra-Orthodox institutions that is the party's pride and joy.
Yesterday morning, Shas actually announced that it was leaving the coalition, but Mr Barak urged its leaders to delay the move for at least 24 hours. "Contrary to predictions," the Prime Minister said last night, "we will be spending the coming weeks and months with Shas by our side."
Most analysts believe Mr Barak will indeed keep Shas on his side, but that the price for the party's loyalty, to be paid in the feverish last days before the budget vote, will be high.