The Big Question: Can Hamas and Fatah ever agree on how to negotiate with Israel?

Why is this question suddenly relevant?

Because Mahmoud Abbas, the Palestinian President, has just issued an ultimatum to Hamas designed to force them to do just that. He has given them until Sunday to agree a document which would mean abandoning their doctrinal commitment to the elimination of Israel and join Fatah in accepting the principle of a two-state solution, with Israel and a Palestinian state living side by side along the 1967 pre-occupation borders. If they refuse, he will put the document to a referendum. If they were to accept now - or after a Palestinian referendum - it could mean a common negotiating stance for the Palestinians in talks with Israel, and would thus remove the ideological conflict between the two groups which - among other things - stopped the formation of the coalition government that Hamas said it wanted after winning the Palestinian parliamentary elections in January.

Don't the signs point more to a civil war than to the two sides working together?

Ten Palestinians have been killed in vicious but sporadic infighting between armed groups this month. And there is a big power struggle between the - elected - Hamas cabinet and the - also elected - president over which should control the 70,000-strong security forces. While Mr Abbas is trying to maintain overall control of security, the Interior Minister, Said Syam, has formed--and deployed - a 3,000-strong "implementation force" - many of whose members were militants in Hamas's Izzedin al-Qassam brigades - with the intention of giving them regular police uniforms and moving them into Gaza police stations to "support" the existing Fatah-dominated police force.

While this is in tune with Hamas's commitment - on which it in part fought the election - to a much needed restoration of law and order, it happened in defiance of a veto by Mr Abbas and is an obvious source of tension between the two groups. Other volatile ingredients are the temptation of disgruntled members of armed groups linked to Fatah to destabilise the Hamas government; bitter resentment within Hamas of some leading Palestinian security chiefs who under Yasser Arafat in the 1990s imprisoned, and according to Hamas, in some cases tortured their activists; and the increasing poverty of security personnel now in their third month without a salary because of the international and Israeli boycott of the Hamas-led PA.

So far, the large majority of the 1.3 million Palestinians in Gaza, where tensions are highest, have shown no interest whatever in fighting an armed conflict, and the incidents, while frequent and dangerous - a Jordanian embassy employee was killed in crossfire as he drove through Gaza City - have been relatively isolated

Also, both Mr Abbas and Hamas's Ismail Haniyeh, the Palestinian Prime Minister, have repeatedly declared that civil war is off the agenda. That said, several Palestinian commentators believe Mr Abbas's proposal for political unity provides the best chance of averting the civil war they fear. "Abu Mazen understands more than anybody else that the alternative to the dialogue is a civil war," wrote the respected Hani El Masri in El Ayyam newspaper last week.

What document does Mr Abbas want Hamas to agree?

Mr Abbas has deliberately made the basis of his dialogue/referendum proposal a joint document drawn up in the Israeli prison of Hadarim by Marwan Barghouti, the jailed "young guard" Fatah leader and his one-time rival for the presidency, and a group of Hamas prisoners led by Sheikh Abdul Khaleq al-Natsheh. The document stops short of explicitly meeting the international demands for recognition of Israel and renunciation of all violence; but, crucially for Hamas, it makes both possible by backing the idea of a "final" agreement on two-state lines. It also proposes a "national unity government" between the two factions. The document matters because prisoners enjoy a special honour and influence within their own factions and beyond.

Reaction within Hamas has been mixed; and not for the first time contradictory statements have been made by some of its leading figures. Immediately after Mr Abbas's speech on Thursday, Dr Aziz Dweik, speaker of the parliament and a leading West Bank figure in Hamas, said the document was a good basis for dialogue and praised the idea of a referendum. But Mushir al-Masri, a prominent Hamas parliamentarian in Gaza, said the plan was a "coup against the democratic choice of the Palestinian people" (of Hamas over Fatah.) There also signs of geographical difference - between Gaza and the West Bank and the occupied territories and the - usually harder line - exiled leadership in Damascus.

What are the arguments within Hamas?

This is a huge strategic decision for Hamas. Although some leading figures have said they would offer a (very) long term truce in return for Israel pulling back to 1967 borders, this would mean signing up, for the first time and in advance of any negotiations, to the idea of a two-state solution. Even supposedly more moderate Hamas figures have argued that Fatah has precious little to show - in terms of a peace process - for its recognition of Israel at the time of the Oslo accords in 1993. On the other hand, endorsement might help to relive the relentless international and Israeli pressure on the Hamas-led PA - and doing so, not because the faction had caved in to that pressure but because it listened to (some) prisoners at the core of the movement.

For Hamas "realists" there might be attractions in not saying "yes" now but letting the referendum decide for them. Hamas spokesman Ghazi Hamad said last week he expected Hamas to "abide by the will of the Palestinian people". (On the other hand, some Hamas figures have been casting doubt on whether even holding such a referendum is practicable.)

What about Fatah?

There are certainly elements in Fatah for whom losing an election has been impossible to accept; and who didn't want to join a Hamas government because they preferred to see Hamas fall, whether because it failed to deliver, or as a result of international and Israeli pressure, together with disruption by armed elements on the inside. But it would be even harder for Fatah than for Hamas to reject the prisoners' call for a joint government.

If Hamas agrees, could peace with Israel be in sight?

If only it were that simple. Israel's premier, Ehud Olmert, is still very committed to a unilateral withdrawal from settlements east of the 450m barrier, while consolidating and expanding West Bank settlements to its west - something which all Palestinian politicians oppose. But if the Abbas plan succeeds it would increase the pressure on Mr Olmert to make the promised negotiations something real, rather than a merely cosmetic prelude to implementing his unilateralist strategy.

Will Hamas ever accept a two-state solution?

Yes...

* A 'yes' vote in a referendum could help Hamas to recognise Israel without unilaterally sacrificing its long-standing ideology

* Now that it has gained some power through the ballot box, Hamas may change its approach, as the IRA did in Northern Ireland

* If the polls are right, willingness to adopt a two-state solution would bring Hamas more in tune with the Palestinian majority

No...

* Hamas's charter says all of Palestine is an Islamic 'Waqf', consecrated for future Muslim generations, which cannot be surrendered

* Hamas has never offered more than a temporary, if 'long', truce; none of its spokesman offers a permanent peace with Israel

* Hamas has often stated that the Oslo agreement, which enshrines the two-state principle, has failed to help the Palestinian people