By Stephen Sackur in Washington

As the whole world knows, Bill Clinton is a master manipulator of the English language.

Remember his classic line during the Lewinsky scandal? "It all depends what the meaning of the word 'is' is"

So it was hardly surprising that his announcement of a breakthrough in the search for peace between Israel and Syria left room for some creative ambiguity.

The White House meeting between the Israeli Prime Minister Ehud Barak and the Syrian Foreign Minister Farouk al-Sharaa will be an historic encounter - the highest level direct encounter between the two countries since the creation of the state of Israel - and it comes after several months of American backroom diplomacy.

The single most important precondition for the resumption of Israel-Syria talks after a break of almost four years was the election victory of Ehud Barak.

Israel's Labour leader promised voters he could deliver peace with Syria and Lebanon - he appears determined to make good on that pledge.

Mr Barak has made reference to the 'wisdom' of Syria's ageing leader President Hafez al Assad; Syrian officials in turn made some unusually positive comments about the courage of Israel's new leader.

And yet Mr Barak's victory brought no immediate rush to resume face-to-face negotiations.

Golan Heights

The problem was a basic disagreement about the significance of promises made and positions adopted during the last round of talks.

The Syrians insisted that Mr Rabin had promised to hand back the Golan Heights, occupied by Israel since the Six-Day War of 1967. Talks would only resume, said Damascus, if Israel re-committed itself to that fundamental principle.

The Barak government rejected the idea that Yitzhak Rabin had promised a full withdrawal. Mr Rabin's offer was described as hypothetical - an effort to gauge exactly what kind of peace Syria was prepared to give in return.

And that is why the Clinton administration saw the need to inject some creative ambiguity into the Israel-Syria track.

The American achievement can be summed up in one phrase. The talks will resume, President Clinton told reporters last Wednesday, "from the point where they left off".

To the Israelis that means no preconditions, no guarantees. To the Syrians it means the return of the Golan Heights remains non-negotiable.

The wily wordsmith President Clinton has ensured both sides can go to Washington in an atmosphere relatively free of bitterness and recriminations.

No easy task

The fact that the talks will take place at the highest level (although President Assad is unlikely to make a personal appearance alongside the Israelis until a deal has been sealed), suggests that the leaders in both Jerusalem and Damascus feel an agreement could be within reach.

Yet it would be wise to be cautious. The fate of the Golan is tied to the kind of "full peace" Syria is prepared to offer the Israelis.

There is the complex question of security arrangements for the Heights after any Israeli pullback, including the possibility of a monitoring role for the Americans.

And no agreement will be implemented immediately. Israel wants to phase any pullback over a number of years and to link it to specific security concessions from Damascus.

Moreover, any agreement signed by Mr Barak will have to be ratified by a national referendum in Israel - a political consideration which rouses deep suspicion in Syria.

Place in history

American officials warn that the diplomatic road ahead remains hazardous.

Nonetheless, both Israel and Syria have good reason to press for an historic agreement.

Mr Barak wants to make history as the Israeli leader who built on the Rabin legacy to deliver lasting peace to his people. A deal with Syria offers the prospect of an end to the costly war in south Lebanon.

For Hafez al-Assad, a president who has suffered from poor health for years, the return of the Golan Heights would represent a national triumph. It might help seal the succession of his son to the presidency.

One more player in this drama has a vested interest in its success: President Clinton.

He has less than a year left in the White House. He would dearly love to engineer a comprehensive peace in the Middle East before his political obituaries are written.