Ordinary Israelis would have been flabbergasted. What, the murderous terrorists marching in line with Israeli peace activists? Israelis marching, talking and joking with the potential suicide bombers? Impossible!

But it was quite natural. All the Palestinian parties took part in the demonstration, together with the Israeli and international activists. Together they ran away from the clouds of tear gas, broke together through the lines of soldiers, were beaten up together. The green flags of Hamas, the yellow of Fatah, the red of the Democratic Front and the blue-and-white of the Israeli flag on our emblems harmonized, as did the people who carried them.

In the end, many of us improvised a kind of protest concert. Standing along the iron security railing, Israelis and Palestinians together, we beat on it rhythmically with stones, producing something like an African tom-tom that could be heard for miles around. The Orthodox settlers in nearby Modiin-Illit must have wondered what it meant.

THE PARTICIPATION of all Palestinian parties was in itself an important phenomenon. It was no doubt encouraged by the Palestinian elections, due to take place this coming Wednesday. It was curious to see the same faces on the posters along our route and right next to us in the crowd.

But it also showed the importance the Fence has assumed in Palestinian eyes.

Years ago, when the construction of the Wall-cum-Fence was just beginning, I went to see Yasser Arafat to suggest a joint struggle against it. I got the impression that the idea that the Wall was a serious danger was quite new to him - the Palestinian establishment had not yet grasped the significance of it. Now it is near the top of the national agenda.

This week, on the eve of the elections in which Hamas is expected to gain a significant share of the vote, the picture of Hamas activists marching side by side with Israeli peace activists, was important. Because soon Hamas will enter the Palestinian Parliament and, perhaps, the government, too.

CONDOLEEZZA RICE sharply criticized the elections because of the participation of "terrorists", echoing the statement of her new Israeli colleague, Tsipi Livni, who declared that they are not "democratic elections" because of Hamas.

What is emerging now is a new pretext for our government to avoid negotiating with the elected Palestinian leadership. The pretext changes frequently, but the purpose remains the same.

First there was the assertion that Israel would not negotiate until the new Palestinian president, Mahmoud Abbas, dismantles the "terrorist infrastructure". That was, indeed, an obligation under the Road Map - but so was the obligation, completely ignored by Ariel Sharon, simultaneously to remove the hundred settlements or so that were set up after his coming to power.

Then came the claim that the Palestinian Authority was in a state of anarchy. How can one negotiate with anarchy?

Now there comes the contention that Israel cannot possibly be expected to negotiate with a Palestinian leadership that includes Hamas, an organization that has carried out many suicide bombings and, at least officially, does not accept the existence of Israel..

The pretexts are manifold, and more can be produced if necessary. (Reminding me of my late friend, Natan Yellin-Mor, former leader of the "Stern Gang" terrorist underground and later peace activist, who said: "I wish God would put in my way as many temptations as I have pretexts for succumbing.")

Hamas' presence in the next Palestinian government is not a reason to reject peace negotiations. On the contrary, it is a compelling reason for starting them at long last. It would mean that we negotiate with the entire Palestinian spectrum (excluding only the small Islamic Jihad organization). If Hamas joins the government on the basis of Mahmoud Abbas' peace policy, it is manifestly ripe for negotiations, with or without arms, based on a hudnah (truce).

Thirty years ago, when I started secret contacts with the PLO leadership, I was almost the only person in Israel in favor of negotiating with the organization that was at the time officially designated as "terrorist". It took almost 20 years for the Israeli government to come round to my point of view. Now we are starting again from the same point.

Why do the Palestinian organizations refuse to give up their arms? Let's not deceive ourselves: for most Palestinians, these arms are a kind of strategic reserve. If negotiations with Israel lead nowhere, the armed struggle will probably be resumed. That by itself is not unheard of. (See: Ireland.)

EVEN IF Mahmoud Abbas wanted to disarm Hamas, he would be unable to. His weak position, combined with the weakness of his Fatah movement makes such a measure impossible.

This weakness, which also finds its expression in the Fawda ("anarchy"), derives mainly from one source: the sly efforts of Sharon to undermine his position.

I have pointed this out more than once: for Sharon, the rise of Abbas constituted a serious danger. Being favored by President Bush as an example of his success in bringing democracy and peace to the Middle East, he threatened the exclusive relationship between the US and Israel, perhaps even opening the way for American pressure on Israel.

To prevent this, Sharon denied Abbas even the slightest political concession, such as releasing prisoners (Marwan Barghouti springs to mind), changing the path of the Wall, freezing settlement, coordinating the withdrawal from Gaza with Abbas, etc. This campaign was successful. The authority of Abbas has been significantly weakened.

Now Sharon's successors are using this very weakness as a pretext to reject serious negotiations with him and the next Palestinian government, calling to mind the story of the boy who, having killed both his parents, threw himself upon the mercy of the court: "Have pity on a poor orphan!"