I've looked at this before when I was shocked by an explanation of how backwards the Saudi monarchical succession system is.
The big question regarding the Saudi succession hangs over whether, and how, the kingship will ever be transferred from the numerous ageing brothers and half-brothers who stand in line after Crown Prince Sultan, to the "next generation" of princes - some of the more senior of whom are already nearing 70 years old.Nothing has really changed since then. The United States supports the Saudi monarchy because, contrary to what would be expected from a democracy, the Saudi monarchy does not use oil fields to fund what George Bush described as "terrorist ambitions". Specifically, Saudi Arabia's greater oil revenues, greater resources per-capita and closer distance to Israel would make a democratic Saudi Arabia far more of an existential threat to Israel than a democratic Iran is.
Earlier this year, King Abdullah named his 76-year-old half-brother Naif ibn Abdul-Aziz as "second deputy prime minister", a position that places him a likely - but not certain - second in line to throne after Sultan.
When King Abdul-Aziz ibn Saud, the founder of the modern Saudi state, died in 1953, he left some 37 sons from his 22 wives. Various of these sons have ruled the kingdom in turn since then.
Many of Abdul-Aziz's sons had a dozen or more sons of their own. Saudi Arabia has no system of "primogeniture" (first-son succession.) Thus, there are hundreds of possible eventual claimants to the throne. Indeed, the youngest of Abdul-Aziz's sons, Prince Muqrin, is, at 64, some years younger than several of the next-generation princes who now hope to become king.
We see what the Americans get out of the relationship. Here is a recollection of Ray Close, one time CIA station chief in Saudi Arabia:
I recall when Prince Fahd bin Abdal Aziz called me to a meeting very late one evening in the early days of the 1973 war and asked me to send an urgent personal message from him to Richard Nixon informing the president that he had felt obliged to contribute a brigade of Saudi troops to the Golan front to support the Syrian offensive there, but that he had personally instructed the commander of the unit not to fire a single shot. That, Fahd told me with considerable emotion and obvious sincerity, was his solemn promise to his American friend.What do the Saudis get out of the relationship? Why was it so important to Saudi Arabia's puppet king that the US president not be angered by this pathetic Saudi gesture? And why would the Saudis make the effort of sending fake troops to Syria to hide their relationship with the United States?
I think there are two primary factors. The first is that in the modern era, weird family dictatorships live on borrowed time. The United States has publicly allocated $75 million per year to overthrow Iran's elected government. Far less than one percent of that would be enough to push the corrupt and effete Saudi dictatorship out of its palaces. Would the alternative be better for Israel? Quite possibly not, but maybe the US could scrounge up an Abbas or Mubarak somewhere in Saudi Arabia - either way it would be the end of King Abdullah's shopping trips to Paris and skiing trips to Colorado, and the threat of that far overwhelms any calculation of national interests or values on the part of the Saudi monarchy.
The second factor is that monarchy inherently leads to a sycophantic outlook on the world. The British decorated his father with the title of king with the understanding that he would be pliant to imperial desires and he has been bred all of his life to seek approval from a foreign ruler - Great Britain as a source of approval has transferred seamlessly to the United States. A person not raised to understand this relationship would be nauseated to see it up close, but Abdul Aziz in 1932 offered up himself and his family almost as a harem of prostitutes for British and later American control in exchange for British assistance in gaining control of a kingdom.
I sometimes see analysts try to back-apply some strategic rationale for Saudi policy. There is none. Saudi policy is as different from what a democratic Saudi Arabia would pursue as the Shah's policy was different from what the Islamic Republic of Iran pursues. In practical terms, the Saudi monarch does whatever the United States tells him to do, though he's learned to distract attention from that relationship with independent-seeming symbolic gestures.
US leverage over Saudi Arabia is really just a quirk of the colonial system left over by the British and maintained despite the fact that the US is not an instinctively colonial nation because of the threat that an independent Saudi Arabia would pose to Israel.