Over the past 10 days, stark new leadership crises have rocked both the Israeli and Palestinian communities and have thrown the ever-tense situation in the Holy Land into a state of grave risk. In Israel, the stroke that Prime Minister Ariel Sharon suffered Jan. 4 rendered him incapable of continuing his job. Day-to-day leadership of Israel's government passed into the experienced and apparently wise hands of Acting Premier Ehud Olmert. But with the commanding figure of Mr. Sharon seriously incapacitated, the longer-term prospects for the bold (if still unilateral) project he was pursuing toward the Palestinians were thrown into doubt.
Among the Palestinians, meanwhile, the political group Fatah, which is headed by President Mahmoud Abbas, suffered a near-complete implosion of internal discipline in the early days of 2006, and it now looks headed for a bruising at the Palestinian legislative elections scheduled for Jan. 25. These elections, which have already been postponed once, may or may not be held on time. Either outcome poses grave risks for Mr. Abbas's ability to retain power in the Palestinian community, and to continue to pursue the peace process with Israel in the same way he has since he was elected president a year ago.
Within Fatah, Abbas has faced a big challenge from younger activists impatient at their own exclusion from decisionmaking and highly critical of the policies that Abbas - and before him Yasser Arafat - has pursued. But Abbas's biggest challenge comes from Hamas, a religious-nationalist movement with a wide reputation for having avoided the blatant corruption and mismanagement that Fatah and its allies have engaged in. So far, Hamas has refused to join Fatah in granting recognition to Israel. That may or may not change.
Back in 1996, when Palestinians last held legislative elections, Hamas refused to take part. This time, it has been extremely committed to participating - though its leaders say their aim in participating is to "bury the consequences of Oslo" that is, the Oslo Accord signed between the Palestinians and Israelis in 1993. However, in their current election campaign the Hamas activists have set aside earlier slogans glorifying armed struggle, focusing on the need to fight Palestinian corruption and to "confront" Israel's continued occupation of the West Bank - without specifying exactly how this should be done.
One highly contentious issue in this election is whether and how the 170,000 Palestinian residents of Israeli-occupied East Jerusalem will be allowed to participate. US Secretary of State Condoleezza Rice has said these Palestinians should be allowed to take part. The terms on which this might happen is one of the hardest decisions Mr. Olmert faces in his early days as Israel's acting premier.
Beyond that, Olmert faces his own tough electoral battle in the Israeli national vote scheduled for March 28. He was one of a number of Israeli politicians who, in late November, joined Sharon in leaving the Likud Party to set up a new, centrist party called Kadima ("Forward"). Kadima also attracted some figures from the Labor Party, including veteran Labor leader Shimon Peres.
Without the charismatic and forceful Sharon at its head, the new party's prospects in March are uncertain. Last summer, a large majority of the Israeli people supported the step Sharon took to pull all Israeli troops and settlers out of Gaza. But it's not clear what support there would be for the additional, significant Israeli pullbacks from the West Bank, including East Jerusalem, that would be necessary for the Palestinians to establish a viable independent state alongside Israel.
With both these peoples living through such deep political crises and uncertainties, there is a real risk of rapidly escalating violence. This, at a time when the US is still acting as Israel's principal outside supporter - and when 140,000 US forces are spread in very vulnerable positions throughout much of Iraq. The potential is huge for a major eruption of anti-Israeli and anti-US feeling across the Middle East.
So far, both Israel and the US have acted sensibly, helping to avoid and forestall acts of escalatory violence. But with the regional situation poised on a knife-edge of potential disaster, the US needs to act quickly to sow new hopefulness in the long-stalled Israeli-Palestinian negotiations. Urgently requesting the UN Security Council to take on new responsibilities for brokering Palestinian-Israeli peace and for helping Washington effect a successful pullback from Iraq now seems like a wise idea.
Sharon underwent several positive transitions in his political thinking and actions in recent years. But the need for a lasting solution to the Israeli-Palestinian issue is so urgent that it cannot await his recovery - and indeed, it must transcend the purely unilateral approach he always stuck to in his diplomacy. As we hope for his recovery, Washington and the rest of the world need to act. In times of great crisis, the values of peacemaking and respect for human equality must prevail - for the sake of all humanity.
• Helena Cobban is writing a book on violence and its legacies.