Has he crossed the Rubicon? And if he has, has he done so only intellectually or also mentally? Is it already possible to number Prime Minister Benjamin Netanyahu among the good guys? And how will we know?

This political-media debate in Israel, endlessly repeated, suffers from a basic weakness: It relies, deliberately, on a baseless assumption that is never explicitly stated - that Israeli willingness for far-reaching concessions suffices to bring peace to Israel.

This assumption was tested twice in the past decade, and both times it proved false: Two Israeli prime ministers, from different parties, in 2000 and in 2008, offered far-reaching concessions to the leaders of the Palestine Liberation Organization, which rejected their offers. So to dispel the harsh impression left by the string of failures that has followed the Oslo concessions, the professional peace processors offered localized excuses: Just give them another round of concessions, and everything will be fine.

But the heads of the PLO feel no need for excuses. In the months after the negotiations with prime minister Ehud Olmert failed, they offered a number of substantive reasons for this failure, which Palestinian Authority President Mahmoud Abbas (Abu Mazen ) summed up with cruel simplicity: "The gaps were wide" (Washington Post, May 5, 2009 ).

A somewhat more detailed explanation was provided recently by United Arab List-Ta'al MK Ahmed Tibi (Haaretz, September 7, 2010 ): "[T]he maximum Olmert could offer in his day did not reach the minimum Abu Mazen and the Palestine Liberation Organization can accept." And knowing the PLO's positions, it is clear that these diplomatic observations are accurate and valid.

In this sense, the Kadima Knesset faction, which is demanding that Netanyahu show them his diplomatic kashrut certificate, has not yet crossed the Rubicon properly. Both members of the faction and its current leader have repeatedly said that the proposals made to Abbas by their former leader, Olmert, went too far and were only his own personal suggestions, to which they never consented. If so, judging by their belated reservations, the maximum they are prepared to offer most certainly does not amount to the minimum the PLO deems necessary for achieving an agreement.

Since our Rubiconists have despaired of the chance that the PLO will change its extreme positions, they have laid down rules for a unique kind of diplomatic physics: For the aspirations of Israel and the PLO to meet, Israel is required to get closer to the PLO's positions, which remain constant, and only Israel is required to make concessions.

Not only have the PLO's leaders held fast to their positions for the past 20 years, but they even boast of it. Abbas recently declared, "We will not relinquish any of our principles. Since the Palestinian National Council convention in Algeria in 1988, at which we [declared] a Palestinian state and recognized [UN] Resolutions 242 and 338, what concessions have we made on our principles? We insist on the 1967 borders, Jerusalem as our capital, and the refugees' rights according to the UN resolutions, especially [Resolution] 194. Our rights to water are also recognized by international law. Not a single word of our documents has been changed, from then to this very day. It has not happened and will not happen" (Al Ayyam, September 6, 2010 ).

True. And therefore, the PLO leadership is not contenting itself with staunch opposition to recognizing Israel as a Jewish state, but is even justifying this openly: "From our perspective, there is the state of Israel and we will not recognize it as a Jewish state. Raising this issue is aimed at denying Israel's Arab citizens their rights and at making them illegal citizens, as well as at blocking any chance of the Palestinian refugees returning to their homes inside Israel" (Abbas, Al-Quds, September 7 ).

The following day, at a press conference in Ramallah, Nabil Shaath said, "The Palestinian Authority will never recognize Israel as the state of the Jewish people. This recognition would directly threaten the Muslims and Christians in Israel and prevent Palestinian refugees, who left their homes and villages several decades ago, from implementing the right to return to them" (Haaretz, September 8, 2010 ).

If so, then the only convincing proof that Israel's government had really crossed the Rubicon would be its adoption of the PLO's demands for reaching an agreement with it. The grievances of our experts on crossing rivers lead to only one outcome: They are saddling Israel with full responsibility for the repeated failures to achieve an agreement with the PLO.

But the logical conclusion to be drawn from the negotiating failures of the past 17 years is in fact the reverse: As long as the PLO persists in its extreme positions, as long as it does not renounce the Fatah platform - which was updated at the organization's sixth convention in Bethlehem in August 2009 and once again reiterated its permanent aim of "destroying the Zionist entity and liberating Palestine" - no Israeli government, from either the right or the left, will be able to achieve a peace agreement.