The Israeli voices have been unanimous, the American voices barely less so: Yasser Arafat, they have chorused, ignoring Palestinian claims to the contrary, has the ability to "turn off" the furious Palestinian street protests the moment he wants to, and thus to halt the bloodshed that ensues.
According to Israel's Prime Minister, Mr Ehud Barak, the Palestinian Authority President seized upon the September 28th visit to the Temple Mount of the Israeli opposition leader, Mr Ariel Sharon, as a "pretext" to abandon the diplomatic process. It would require only "a clear order" from Mr Arafat, says Mr Barak, for calm to be restored.
Ms Madeleine Albright, speaking on US television, was only slightly more equivocal. Mr Arafat "has responsibility for controlling violence", she said. "We think he should do more."
But this weekend, for the first time, one respected voice sounded a discordant note - an Israeli voice at that: Mr Ami Ayalon, who until a few months ago headed the Shin Bet, the internal Israeli intelligence agency, and thus had some of the best available sources of information about who really wields power in the Palestinian territories.
In an Israeli TV interview, Mr Ayalon, who is no opponent of Mr Barak's, nevertheless contradicted his Prime Minister by arguing passionately that Mr Arafat had "no ability whatsoever to control" unfolding events in the West Bank and Gaza Strip, had been "completely startled" by the violence, and that his rule was "weaker than ever before."
While heading the Shin Bet, Mr Ayalon consistently asserted that Mr Arafat was a viable peace partner, genuinely bent on reconciliation with Israel, and committed to working with Israel to prevent attacks by Islamic extremists. That view has been widely discredited in Israel during the past 18 days of violence, with some Israeli officials even claiming that Mr Arafat's Machiavellian planning had extended to sending provocateurs to fuel several days of violent Israeli Arab demonstrations.
Where Mr Ayalon's views do echo, of course, is on the Palestinian street - where, as the Palestinian legislator, Ms Hanan Ashrawi, observed yesterday, there is now serious opposition to Mr Arafat's participation in summit talks and to a return to peace negotiations, and where signs are growing that various paramilitary organisations, while nominally loyal to Mr Arafat, may not be inclined to heed his authority.
Mr Marwan Barghouti, the head of the Tanzim paramilitary fighters in the West Bank, for instance, is emerging as an increasingly prominent independent voice. Masked gunmen in Nablus have for days been holding marches deriding the Palestinian bureaucrats and touting the armed struggle as the means of countering Israeli aggression.
At the funeral of a Palestinian man in Hebron yesterday, a new militia was openly recruiting members, and the body was paraded through the streets while gunmen, firing into the air, called for "revenge" and shouted "Down with the olive branch, long live the rifle."
For Mr Barak, the release from Palestinian jails of dozens of Hamas and Islamic Jihad activists in recent days has been seen as a virtual invitation by Mr Arafat for a new spate of suicide bombings.
But some Palestinian sources say that many of the releases came as jails were emptied because of Israeli warnings that they might be targeted in air attacks, and that others were effectively forced on Mr Arafat by angry mobs converging on the prisons.
Yesterday, it was reported that more than 30 of the militants had been rearrested. Mr Barak is demanding that they all be re-imprisoned. The Prime Minister believes Mr Arafat does not want to keep the Islamic militants behind bars. His former top security chief believes Mr Arafat does not dare to keep them there.
US President Bill Clinton is due to arrive at Sharm el-Sheikh this morning to take part in the Middle East summit, according to a source close to the Egyptian presidency.
Mr Clinton is due to meet Egyptian President Hosni Mubarak two hours later, the source said last night,
Mr Mubarak is then scheduled to hold separate talks with Mr Arafat, Jordan's King Abdullah II, and Mr Barak.
The summit itself should start in the afternoon, and will also include UN Secretary General Kofi Annan and the EU security and foreign policy representative Mr Javier Solana.