King Fahd’s long illness had given the Saud ruling family plenty of time to plan for his death, and the succession of his half-brother, King Abdullah, yesterday went as smoothly as anticipated.

Subsequent successions, however, are unlikely to be as painless. The July 20 resignation of the Saudi ambassador to Washington for 22 years, Prince Bandar, and the announcement that he will be replaced by the current London ambassador, Prince Turki Al-Faisal, were clear signs that jostling had begun.

Prince Bandar’s dramatic return to Riyadh allows him to lobby for a role in the shadow of his father, the defense minister, Prince Sultan, who was made crown prince yesterday.

Prince Turki, meanwhile, is a brother of the foreign minister, Saud Al-Faisal, who announced Prince Bandar’s resignation in Riyadh last week. Prince Saud is King Abdullah’s closest ally.

Prince Turki’s posting to Washington, in other words, marked the opening shots of King Abdullah’s campaign to wrest control from his half-brothers, by appointing his own people to key positions.

The succession, though, could not have come at a better time. Saudi Arabia is flush with oil money, and King Abdullah recently completed a successful visit to President Bush. King Abdullah, moreover, is the first king since Faisal, who ruled from 1964 to 1975, to be popular among the Saudi masses. He has positioned himself as a strong Muslim leader by providing funding for the pious and uniting the kingdom’s warring factions. He has an undeniable bond with the impoverished and disenfranchised in Saudi society, even visiting slums to hear the concerns of their inhabitants.

But King Abdullah, even if he turns out to be a reform-minded king like Faisal, is at best a short-term answer. He is 79, and his health cannot be relied on. Prince Sultan himself is 76, and while King Abdullah was a half-brother of Fahd, Prince Sultan was a full brother who shared the same mother.

Family rivalries always lurk in the background, and it is conventional wisdom that Prince Sultan and King Abdullah loath one another. The royal family’s sensitivities to open discussion of succession and any hint of dissent within its leading ranks were dramatically apparent in 2003. The then American ambassador, Robert Jordan, was ordered out of the kingdom, a London-based Arab newspaper claimed, after he voiced Washington’s support for King Abdullah to succeed Fahd with a member of the younger generation of princes becoming the next crown prince.

The dominance of the sons of the founder of modern Saudi Arabia, King Abdul Aziz, and the opportunity of each to serve as monarch are one of the kingdom’s most distinctive traits. Abdul Aziz had at least 40 sons. They could overlook their own jealousies, if not for the common good then at least to maintain their position in the hierarchy. That is far more difficult for the so-called third generation of princes who have six fathers, many mothers and countless half brothers in their own ranks.

The passing of the second generation, of whom Prince Sultan and interior minister, Prince Naif, are the last, is not far off, and is likely to lead to competition that could be profoundly destabilizing. The royal house has shared out responsibilities to keep all branches of the family happy, with each region of the country being governed as a quasi-autonomous fief. All the more dangerous is the fact the various armed forces are commanded by competing princes.

Ensconced in their power, jealous of their privileges, and faced with new challenges to their status, they may have to fight to maintain their authority.