By Jeremy Bowen
Middle East editor, BBC News
Another Middle East peace summit is coming up in the United States, but there are risks in holding summits on the Israeli-Palestinian conflict and one of the main parties to the conflict, Hamas, is being excluded.
At the moment, the summit looks likely to start in Annapolis, Maryland, on 15 November.
Palestinian and Israeli leaders want different things from the conference
Israeli Prime Minister Ehud Olmert and Palestinian Authority President Mahmoud Abbas are having regular meetings about it.
They are trying to produce an agreed document about the future. Mr Abbas wants more detail. Mr Olmert wants something pretty vague.
For the summit to succeed, for any of this to mean something, it has to result in a concerted attempt to tackle the so-called "final-status issues".
These are the politically radioactive problems - about the future of Jerusalem, borders, water, refugees and settlements - that have to be sorted out before there can be any chance of setting up a Palestinian state alongside Israel.
That, after all, is the policy of the summit host, United States (and of many other countries, but the US is the one that matters).
The way that the final-status issues are dealt with will determine what kind of state a future Palestine might be - and whether the peace settlement would last.
Tony Blair, the envoy of the Quartet of the UN, US, EU and Russia is also working towards the November meeting.
He believes that it will be clear by the end of the year whether this process is going anywhere. In other words, it has to lead to serious final-status talks.
Mr Blair - following the lead of the US Secretary of State Condoleezza Rice - will talk about a "'political horizon" for the Palestinians. This means a glimpse of what the process might deliver them.
There is a theory, popular among Western policymakers, that this is the most favourable moment since before the outbreak of the second Palestinian uprising in 2000 to talk peace.
It is based on the idea, first of all, that Condoleezza Rice seems prepared, for the first time, to get properly stuck in.
Also, Mr Abbas needs a success, to help him improve his domestic position.
Ditto Prime Minister Olmert.
There is also a belief that the so-called Arab Quartet of Egypt, Jordan, Saudi Arabia and the United Arab Emirates are now much more concerned with Iran, its nuclear programme and jihadist Islam than they are with Israel and the Palestinians, and therefore want to get the issue dealt with.
Well maybe. But there are questions about how much spadework the Bush Administration really is prepared to do before November - a lot is needed, because so little has been done in the last six and a half years.
And there are some very serious holes in the proposed summit's structure.
The biggest is that it ignores Hamas, the Palestinian militant faction which seized internal control of the Gaza Strip from its rival, Fatah, in June.
Because Hamas will not recognise Israel, renounce violence, or accept previous Palestinian agreements with Israel, it has not been invited.
Collapsed economy: Nearly 80% of Gazan's receive UN food rations
That position is consistent with the line that the Quartet and Israel have taken since Hamas came to power in a democratic election early in 2006.
But what the policy ignores is the fact that Hamas has the capacity to wreck anything that comes out of the summit.
The anti-Hamas policies of Mr Olmert and Mr Abbas - and their Western backers - seem to boil down to showing Palestinians how much better life would be if Hamas was not in power.
Hamas has been isolated even further by Israel and by Mr Abbas's Fatah movement since it took over Gaza in June.
Life in Gaza is getting harder and harder. Gaza, in its entirety, has been designated a "hostile entity" by Israel.
That comes on top of an embargo that has brought the economy of the Gaza Strip to a state of collapse.
Holding summits about the Palestinian-Israeli conflict is risky. If they fail, it is not just a question of going back to the drawing board
The jobs that are left - and there are not many of them - are disappearing. About 1.4 million people live in the Gaza Strip. Some 1.1 million receive UN food rations.
Gaza's new "hostile" status allows Israel to institutionalise things it was already doing, and to turn the screw a little harder.
It also makes the collective punishment of Gaza's citizens, which contravenes the fourth Geneva Convention, into a firm government policy.
Israel's main motivation in naming Gaza as a hostile entity is its inability to stop the rocketing of the border town of Sderot.
A big military operation last year could not stop the rockets, and killed so many Palestinians that it was seen by many people around the world as disproportionate.
But the Israeli government needs potential voters to see it doing something, hence Gaza's new status.
Israeli Defence Minister Ehud Barak has also said publicly that another major military push is coming if the rockets do not stop.
Letter from diplomats
In a recent letter to Condoleezza Rice, a group of former American diplomats called for the inclusion of Hamas in the November summit.
They said that "saying no to Hamas without planning for the consequences is a likely ticket to new problems".
One of their suggestions is for Washington, which is hoping for a good Arab turnout at the summit, to insist that everyone who comes must accept a Saudi-sponsored Arab peace initiative.
Broadly, it offers full peace in return for a full Israeli withdrawal from land captured in 1967, plus a "'just solution" for Palestinian refugees. Israel has not signed up to either.
Another group of senior Americans - retired lawmakers and officials, including two former national security advisors, Zbiegniew Brzezinski and Brent Scowcroft - has also intervened with a letter to Mr Bush.
They call for a dialogue with Hamas - and also with Syria - they concede this would not be easy, suggest talks could start with a ceasefire, and say that Hamas includes realistic people, who do not want a permanent state of war and conflict.
And they issue a warning: "Because failure risks devastating consequences in the region and beyond, it is critically important that the conference succeed."
Holding summits about the Palestinian-Israeli conflict is risky. If they fail, it is not just a question of going back to the drawing board.
The last big one, at Camp David in 2000 was a disaster. Bill Clinton, in the last few months of his presidency dragged Yasser Arafat and Ehud Barak, then Israel's Prime Minister, into a double-or-quits meeting.
President George W Bush's people are so nervous about a repeat of that summit that there have been attempts to brand November's event as a "meeting".
They are still trying to dampen expectations, not all that successfully, since this is President Bush's first proper diplomatic initiative towards the Palestinians and the Israelis since he took office in 2001.
When the Camp David summit collapsed it sucked hope out of the region and a couple of months later there followed the second Palestinian intifada. No-one wants another one of those.