Leaders have failed to solve rifts, dampening expectations for the summit
Arab League members meeting in Qatar this week are united in condemning the international arrest warrant for Sudanese President Omar al-Bashir. But the BBC's Jim Muir, in Beirut, says they seem to agree on little else.
The Qatar gathering appears doomed to fall far short of what some had hoped it would be - the crowning moment for inter-Arab reconciliations that would see a closing of ranks in the face of major regional challenges.
A rift has grown in recent weeks, symbolised by the glaring absence of President Hosni Mubarak of Egypt, the most populous and arguably most politically weighty Arab state, one which ironically normally aspires to the role of chief regional broker and conciliator.
A bonding strategic understanding between the Arab nations is seen as particularly important at the moment, in the face of at least two significant issues.
Hosni Mubarak's absence is a serious blow to hopes of Arab unity
One is the expected emergence of a new, largely right-wing government in Israel, whose commitment to the widely-accepted premise for peace with the Palestinians - two states living side by side - is in some doubt.
The other is the role of Iran, which Saudi Arabia and some other conservative Arab states fear could be bolstered by the dialogue which US President Barack Obama says he wants to open with Tehran.
The weeks preceding the summit have seen a series of moves aimed at bringing about a healing of long-standing rifts.
Some progress was made. But the absence of such a key player as Mr Mubarak - whose place was taken by a low-ranking minister - made it clear that there is still a long way to go.
The basic divide is between those countries seen by their adversaries as being in thrall to the US, such as Egypt, Saudi Arabia, Jordan and other conservative states; and those seen by the latter as being in league with Iran, such as Syria, Qatar and others.
Syria, which makes no secret of its strategic alliance with non-Arab Iran, has seen a perceptible warming of its relations with Saudi Arabia recently, and to a lesser extent with Egypt.
But it has refused to break with Tehran, and the basic rift remains.
The same issue largely underlies Egypt's unseemly row with Qatar and Mr Mubarak's boycott of the Doha summit.
Qatar and its international satellite channel al-Jazeera deeply offended Cairo by their criticism of Egypt's role during the Israeli onslaught on Gaza earlier this year, and their support for Hamas in its negotiations over inter-Palestinian reconciliation.
Many in the West want Mr Bashir tried for atrocities in Darfur
Qatar has also implicitly challenged Egyptian political and diplomatic clout by sponsoring settlement moves in Yemen, Lebanon and Darfur, with considerable success.
A Doha summit which managed to heal inter-Arab rifts would have a sharp and immediate beneficial impact in several important arenas.
One of the factors impeding progress on peace between Israel and the Palestinians is the bitter split between the pro-western, Fatah-dominated Palestinian Administration headed by Mahmoud Abbas, and the militant Hamas movement, which controls Gaza.
Egypt's strenuous efforts to sponsor a reconciliation and produce a Palestinian national unity government have foundered, amidst accusations that Iran and its regional allies have been running interference and encouraging Hamas to be obdurate.
If all the main regional players were working in harmony, it is believed that Palestinian reconciliation would be easier to achieve.
It would also be expected to ease tensions in Lebanon, for decades a cockpit for regional struggles.
The country faces general elections in June in which the opposition, backed by Iran and Syria, will be trying to wrest power from the current pro-western majority.
The recent signs of a thaw between Saudi Arabia and Syria have already gone some way towards assuaging fears of serious trouble over the Lebanese elections, but nothing is sure.
Issues such as Iran's role are so sensitive that they are not even on the Doha summit agenda.
Real Arab unity of purpose may well be doomed to await the emergence of a concerted US Middle East policy
Despite the rifts, there will be some issues on which the Arabs can agree.
They have already taken a strong position rejecting the arrest warrant issued on 4 March by the International Criminal Court (ICC) against President Bashir, a stand that is expected to be endorsed by the summit.
The Sudanese leader defied the warrant by flying to Doha for the summit, having already visited Eritrea, Egypt and Libya after the ICC decision was announced.
The Arab states see it as an issue of sovereignty. Only three Arab League members - Jordan, the Comoros Islands, and Djibouti - are signatories to the agreements underpinning the ICC.
The summit is also expected to see broad agreement that the Arab peace initiative, announced in Beirut in 2002, should remain on the table but with a warning that its shelf-life would not be indefinite.
The initiative, sponsored in particular by Saudi Arabia, offers Israel comprehensive peace with the Arabs in exchange for giving up lands seized in the 1967 war.
However, consensus on that issue will remain merely ink on paper - like the initiative itself - if strategic inter-Arab differences continue to block the modalities for moving forward towards peace.
Like many previous top-level pan-Arab gatherings, the Doha summit is likely to be fundamentally inconclusive, despite carefully-tuned political declarations.
Real Arab unity of purpose may well be doomed to await the emergence of a concerted US Middle East policy bent on resolving the region's contradictions rather than exacerbating them, as the previous administration's policies succeeded in doing.
Much will depend too, on the outcome of Washington's overtures towards Tehran.