THE ARAB SUMMIT called to endorse the Saudi peace plan collapsed. Syria was the spoil. It could play this role because, despite its low landing outside the Arab world, inside it has the high fatus of a front-line state closely aligned with the PLO; it also has, in Libya, a second patron besides Saudi Arabia. Supposedly the masters of a sinuous il-backed diplomacy, the Saudis got out ahead of the Arab curve. Though Israel had rejected their plan as offering too little in the way of eventual recognition, the other Arabs found the Saudis offered too much. Whether the Saudis will get back out in front looks doubtful. Whether they will reduce their peace-keeping in Labanon and drop their Syrian brothers back into the soup there seems less doubtful. Lebanon is the likely site of the next Mideast fire.

It's some consolation that the Saudi plan aborted before it was truly launched, rather than after, when the wreckage might have included more than the royal family's pride. But otherwise the crash is a genuine disaster, not so much for the Saudis as for the Israelis and Palestinians.

Israeli officials, after the summit, said the crash proved the unworthiness of American faith in Saudi leadership and the general unreadiness of Arabs to move toward peace. This lesson comes poorly from a government that took what steps it could to discredit the Saudi overture, including overflights of Saudi territory and threats to answer the plan's eight points with "eight new West Bank settlements." Smart Israelis, hawks included, could see the promise of eventual Saudi recognition, but the Begin-Sharon annexation-minded view, which prefers territory, prevailed.

Though PLO chairman Yasser Arafat had earlier indicated favor for the plan, at the summit he caved to the dissidence within his group and withheld his support. The PLO's standard complaint against Camp David is that from the start the PLO itself was on the outside. Here it let pass a chance to get in at the beginning.

So the Saudi safety net is unstrung. There remains the Camp David high wire. The Israelis had feared lest attention be drawn outside the one Mideast peace process established on their terms. They suggest that the United States now spare no effort to make those talks succeed. But American recommitment to the process is no substitute for Israeli dedication to the purpose, which is, as Egypt keeps underlining, to grant West Bank Palestinians enough autonomy to draw them in. No one should underestimate the difficulties: PLO murders of would-be collaborators, for instance. But Mr. Begin knew this when he signed on.