The mothers of dead children in Gaza cry to heaven for mercy and for vengeance. Meanwhile, Israeli public relations spokespeople go through their paces, pointing to Hamas's refusal to renew a truce and the rain of rockets from Gaza onto Israel. The UN Security Council, the White House, and the Foreign Office issue predictably futile statements. Another wretched phase in the Israeli-Palestinian conflict seems to be opening.

How can the bloody stalemate be broken? Three things are necessary: first, a clear picture of the ultimate objective; secondly, short-term steps to prepare the ground; thirdly, ongoing commitment by all parties for the longer term. The ultimate objective must be two national states, Israel and Palestine, living side by side, at peace, without territorial or other claims on each other.

Two states, not one, as the Israeli far Right wants, with its colonialist vision of domination. Two states, not one, as Hamas and its fanatical Islamist supporters want, with their vision of a Taliban-style Muslim republic in which Christians and Jews would live, if at all, on sufferance.

Two states that answer the legitimate national aspirations of Palestinians and Israelis, not one bi-national state in which civil strife would be predictably massive and ongoing.

The two states must have agreed borders within which the issues of refugees, settlements, and Jerusalem will no longer bedevil relations. The frontier must be the 1949-67 armistice line, with minor agreed adjustments.

Why that line? Because anything significantly less will not provide even the minimum territorial basis for a viable Palestinian state.

Why any adjustments at all? Because equitable, mutually agreed exchange of land affords the best basis for the defensibility of both states. After all, there is nothing sacrosanct in inter-national law about armistice lines.

Israel must withdraw from most of its settlements in the West Bank, retaining only some near the "green line", in return for which it will have to yield an equivalent area to Palestine.

Greater Jerusalem, with its roughly equal populations of Jews and Arabs, living in segregated ethnic neighbourhoods, will have to be redivided - not by a wall but as an open city with two recognised sovereignties and shared infrastructure and urban planning. Why? Because nothing else has the remotest chance of working.

The refugee camps in Lebanon and elsewhere, in which Palestinians driven out of their homes upon the creation of Israel in 1948 and their descendants still fester, must be emptied. Those who wish to return must be allowed to do so - to Palestine, not Israel. Others, with international assistance, must be enabled to settle in their countries of residence, elsewhere in the Middle East, or in western countries.

Why should they not all return to Israel? For the same reason that the 13 million Germans expelled from eastern Europe after 1945 and the one million Jews driven out of Arab lands after 1948 cannot return.

There is little or nothing for any of these people to return to. Their homes, lands, and livelihoods are all gone. The clock of history has moved on and its hand cannot be turned back.

They all can no longer hope for absolute justice but, like the surviving remnant of Jews in post-war Europe, they deserve a historic reckoning that should include due compensation and a humane resolution of their current predicament.

These objectives are not pie-in-the-sky. Broadly speaking, they command the assent of the Israeli government and the Palestinian Authority as well as of the international community, including the "Quartet" (the UN, United States, EU, and Russia) and the Arab League. Most importantly, they are what the broad middle ground of Israelis and Palestinians (as shown in public opinion polls) want - or are prepared to accept.

How, then, do we get there? First, the short-term. Israel and Palestine are both in the throes of bitter leadership struggles. These must be resolved quickly. The international community should help ensure that peacemakers on each side triumph over warmongers. In Israel, elections are due in February. The best hope for more moderate forces is the Foreign Minister, Tzipi Livni, leader of the Kadimah Party.

But she is hamstrung by the continued presence of the utterly discredited Prime Minister, Ehud Olmert. In the face of a corruption scandal, he has announced his resignation but remains in office pending the election.

He should be pressed to leave the scene completely and make way for Livni as effective head of government (as happened before the election of 1977 when Shimon Peres replaced Yitzhak Rabin).

Barack Obama could invite Livni to visit him in the White House shortly after he takes office on 20 January. Interference in Israeli elections? Definitely! It has happened before and is urgently needed now.

The Palestinians, too, are due for elections in early 2009. The opponents of Hamas need help. The first action of a newly elected Israeli government should be to release the imprisoned Fatah militant Marwan Barghouti.

He is the only secular Palestinian leader with a serious prospect of trouncing Hamas in elections. He has shown pragmatism in the past.

His moment has arrived. The United States and the EU should press for his release. And Israel must take real steps, not mere token gestures, to ease conditions of life for Palestinians in the West Bank and Gaza to show that peace is a real option rather than merely a propaganda slogan.

With Livni and Barghouti installed, the way would be open for the incoming US administration to broker a comprehensive settlement. Washington cannot simply press a button and produce peace. But it can improve on the miserable record of the Bush administration. No new magic formula is required but serious commitment and continued resolve could achieve results.

We should listen to the shrieks and cries of the bereaved women of Gaza. There is a political and strategic price to be paid if we do not. Beyond that, our common humanity demands it.

* Bernard Wasserstein is professor of history at Chicago University and author of Israel and Palestine: Why They Fight and Can They Stop?

• 

  Daughter of Anne Robinson: Mum offered to buy me Botox for my wedding. I was like: 'I'm sorry?'

  Emma Wilson reveals exactly what it's like to be Anne Robinson's daughter — and about stepping out from under her shadow

  ---

• 

  Flame and glory: Rammstein set to light up London

  Sound check: German industrial metal band Rammstein literally play with fire in their live performances - and now they are about to unleash their singeing spectacle on London. Watch out for your eyebrows

  ---