DUBAI Saudi Arabia is anxious to show its allies there will be no power vacuum in the world's biggest oil exporter as health problems beset its octogenarian rulers, but the danger of open disputes over succession remains.
King Abdullah heads to New York on Monday for treatment of a blood clot and slipped disc and Crown Prince Sultan makes a hasty return on Sunday after over two months in Morocco following almost two years of unspecified health problems.
A series of official announcements over the past week on the king's health stand in contrast to the more opaque manner in which such affairs were handled in the past -- reflecting a desire to reassure decades-long ally Washington that the ruling family's handle on affairs remains firm in tense times.
"Everybody should know that we do have a system to resolve all unexpected situations. We know that Prince Sultan was ill and now we know the king is ill," said prominent Saudi journalist Jamal Khashoggi, who is close to key princes.
"There will not be a vacuum because the allegiance council specified things. There is a system," he said, referring to a council of senior princes set up by Abdullah to ensure consensus on future decisions on who becomes crown prince.
Though the Gulf Arab state controls more than a fifth of the world's crude reserves and is a major holder of dollar assets and a major U.S. ally, it has no elected parliament or political parties. Its king is around 86 or 87 and his crown prince only a few years younger.
As home to Islam's holiest sites as well as birthplace of al Qaeda leader Osama bin Laden, Saudi Arabia is key to global efforts to fight Islamic militancy.
Washington wants Riyadh to continue social and economic reforms promoted by Abdullah that were seen as crucial after mainly Saudis carried out the Sept. 11 attacks of 2001.
But confusion still swirls over the real state of health of both men and what will happen to Abdullah's policies.
Western diplomats in Riyadh -- who often compare the game of analysing policy and personnel moves in the notoriously closed dynasty to Kremlin watching -- say they remain in the dark.
When the state news agency said last week that Abdullah's son Mitab would take control of the National Guard, an elite Bedouin corps that handles domestic security, it shied away from stating directly that the king had relinquished control.
"The place of Saudi Arabia is now is so important considering Yemen, Iraq, Iran, Afghanistan -- Washington and all the West really need stability in Saudi Arabia," said Mai Yamani, a Saudi analyst based in London.
A Saudi intelligence tip-off helped Western governments stop package bombs destined for the United States that were sent on planes out of Yemen last month. Riyadh plans to buy up to $60 billion worth of arms from the United States, in what analysts see as a U.S.-Saudi efforts to challenge rising power Iran.
While official media seek to present family unity, tensions remain between the senior princes over who will run the country and over securing positions for their sons in the future political architecture of the absolute monarchy.
Rulers have so far all been sons of founder Abdul-Aziz Ibn Saud and many of the 18 million Saudis want to see the gerontocracy pass power on to a new generation.
Abdullah appointed Interior Minister Prince Nayef, his comparatively youthful half-brother at around 76, as second deputy prime minister last year, making it clear who will be in charge when both king and crown prince are indisposed.
But the position did not guarantee Nayef would become king, after Abdullah refrained from appointing a deputy crown prince when he took power in 2005 in what was seen as a sleight aimed at Nayef -- who for long denied Saudis were behind 9/11.
Nayef has expanded his influence beyond security to make public statements on economic issues and some government offices and websites carry his picture alongside Abdullah and Sultan.
At stake is the personal legacy of leading figures of the Saudi family since the 1970s.
Nayef is seen as a hawk who is lukewarm about the social and economic reforms the king has promoted, including attempts to reduce the influence of the hardline clerical establishment in a country that imposes strict Islamic sharia law.
After promoting his son, the king on Sunday extended some key backers of his reform policies in their positions, including top official cleric Grand Mufti Sheikh Abdul-Aziz Al al-Sheikh and the Saudi ambassador to Washington Adel al-Jubeir.
Theodore Karasik, a Dubai-based defence and security analyst, said elements of foreign policy were also at stake if Nayef ever became king.
"My assumption is that Nayef is more hawkish on Iran so there could be changes in foreign policy," Karasik said.
Washington-based analyst Simon Henderson said Sultan's return not only showed he still had ambitions to be king but that he wanted to bolster the position of his own family following Abdullah's promotion of Mitab.
Sultan's son Khaled is his deputy defence minister and Nayef's son Mohammed is deputy interior minister.
"Sultan probably feels some pressure to come back home," he said, adding Sultan's chairing of the weekly cabinet meeting on Monday could signal his determination to remain at the helm.
It is not clear to what degree Sultan will be able to take control of affairs in the king's absence. Officials say he has been working normally but diplomats say he has been much less active in public since treatment for what they was cancer.
Abdullah was de facto ruler for years after King Fahd was incapacitated by a stroke. "This is not the first time there is this type of movement taking place," said Saudi politics professor Khaled al-Dakhil.
(Additional reporting by Asma Alsharif and Ulf Laessing; Editing by Samia Nakhoul)