Solutions will be hard to find Tuesday when Gulf monarchs hold their annual summit in a region threatened by jihadists and a war in Yemen that has raised tensions with Iran.
"You go down that list, it's very complex," Anthony Cordesman, of the Center for Strategic and International Studies in Washington, said of the challenges facing leaders of the oil- and gas-rich region.
The six Sunni-dominated Gulf Cooperation Council states will gather in the Saudi capital, still worried that Shiite Iran might be able to develop an atomic bomb.
Their concerns persist despite assurances from Washington and Paris that an international accord being drafted aims to prevent that.
A framework agreement between Tehran and the United States, France and other major powers limits Iran's nuclear capabilities in return for a lifting of international sanctions.
French President Francois Hollande will attend the GCC summit, making him the first Western leader to do so since the bloc's creation in 1981.
The visit will reinforce a deepening of Saudi ties with major powers beyond the United States.
Hollande will join rulers from Bahrain, Kuwait, Oman, Qatar, Saudi Arabia and the United Arab Emirates.
They will gather just over a week before the Gulf leaders travel to traditional ally Washington. President Barack Obama called that meeting in a bid to allay their fears over any US rapprochement with Iran, and to brainstorm on reducing regional conflicts.
Most Gulf states support a US-led coalition bombing jihadists from the Islamic State extremist group in Syria and Iraq since last year.
IS has seized swathes of territory in the two countries, and has threatened Saudi Arabia.
Last month the kingdom said nearly 100 jihadists, mostly linked to IS, have been arrested and several plots foiled, including one against the US embassy.
Riyadh organised its own coalition this year in an effort to stop the advance of Iran-backed Shiite rebels in neighbouring Yemen.
But pro- and anti-government forces continue battling in Yemen's second city of Aden, aid groups warn over the humanitarian situation, and Al-Qaeda has seized territory in the resulting chaos.
Riyadh feared the Huthi rebels would take over all of Yemen and move it into Iran's orbit.
Oman is the only Gulf state outside of the coalition which has bombed the rebels daily since March 26 to support the exiled government of President Abedrabbo Mansour Hadi.
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- Rhetoric versus reality -
"All of these are issues where... any given meeting makes progress but it doesn't reach solutions," Cordesman told AFP, questioning the degree to which GCC members cooperate with each other.
"The problem often is the rhetoric is good, the reality isn't."
The GCC was founded to more deeply integrate the Gulf countries.
The Saudi regime will be under scrutiny at the summit six days after King Salman announced a new heir and made a son second in line to rule.
The appointments of Crown Prince Mohammed bin Nayef, 55, and Deputy Crown Prince Mohammed bin Salman, in his early 30s, confirmed a shift to the next generation of leadership.
Riyadh and Tehran are rivals for regional influence.
They were already divided over Syria, where Saudi Arabia backs Sunni-led rebels and Iran supports President Bashar al-Assad's regime, but the war in Yemen has worsened relations.
Iran has dismissed as "utter lies" accusations that it armed the Huthis, although a UN panel of experts found a longstanding "pattern of arms shipments to Yemen by sea".
The Saudi-led coalition has imposed an air and sea blockade of Yemen, but Iran has sent warships to nearby waters.
Tehran's navy says two of its destroyers have reached the Bab al-Mandab strait between Yemen and Djibouti to protect Iranian commercial vessels.
US naval forces have also begun "accompanying" American-flagged commercial ships traversing the strategic Strait of Hormuz between Oman and Iran, after Iran seized a cargo vessel.
On Thursday, Gulf foreign ministers rejected holding talks on neutral ground between Yemen's rival political forces, as sought by Tehran.
They said the GCC should host talks in Riyadh.
Cordesman said Yemen's fundamental problems, including ethnic and tribal divisions, have not been properly addressed by the Gulf.
"You can't bomb your way into Yemeni unity," he said.
"You have a strategy that's maybe achieving a very narrow goal, but Yemen was a failed state before the bombing and Yemen will be a failed state after the bombing unless you can address those other issues."