The news on Sunday that the deputy Saudi defence minister Prince Khaled bin Sultan had been removed from his post comes after a series of position changes among senior Saudi princes that have sped up in recent months as King Abdullah closes in on 90 years old, if he isn’t already there. Things began to heat up in earnest from 2009 when veteran interior minister Prince Nayef, like Abdullah, one of the first generation of sons of the modern state’s founder King Abdulaziz, was made second deputy prime minister, a surprise move from a king who was known not to get on with a powerful half-brother seen as the real strongman on the ground. Nayef died last year, since which time the jockeying among the sons of the main sons of Abdulaziz – Abdullah, Fahd, Nayef, Salman, Sultan – has intensified dramatically, or at least what we might call dramatic in the Saudi context.

Khaled’s ouster comes in that context. It is a ruthless battle of lobbying and intrigue inside the family in which the weakest among those key grandsons will fall. Without his father Sultan to protect him, Khaled bin Sultan was a sitting duck. He performed badly during the war with the Yemeni Houthi movement four years ago and failed to secure the ministerial job when Sultan, defence minister for years, died in 2011. Abdullah’s chosen crown prince, Salman bin Abdulaziz, was given the defence post instead. But Salman has Alzheimer’s and cannot properly function, so his son Mohammed is de facto in charge of affairs.

According to the insider Tweep @Mujtahidd, Prince Mohammed bin Salman needed to wait for his chance to deliver the fatal blow to Khaled, who Abdullah was still reluctant to jettison. That chance came in recent weeks after Khaled apparently tried to arrange a new purchase of Chinese medium-range ballistic missiles during a trip to China for other business in his capacity as deputy minister. No official reports confirmed this, though it was rumoured by some outlets, but Mujtahidd says it angered the U.S. government, coming as the US Defence Department seeks to finalize a $10 billion arms deal with Israel, Saudi Arabia and the United Arab Emirates this month.

وهناك كان التصرف الذي اوقعه وهو خروجه عن إطار رحلته للصين والتفاهم مع الصينيين لتجديد منضومة صواريخ (سلك وورم) دون تنسيق مع الملك

— مجتهد (@mujtahidd) April 20, 2013

Rivalry among key grandsons involves a battle for resources. The defence ministry is infamously the place where the biggest kickbacks for princes are to be made, as the accusations over the years of corruption involving the Yamamah defence contracts with British Aerospace/BAE Systems testify to. Now that the Saudi defence ministry is solidly in the hands of Salman’s wing of the family, Prince Mohammed will be able to deal with a second-tier prince, Prince Fahd bin Abdullah bin Mohammed, grandson of a half-brother of Abdulaziz, who will be a loyal servant since he has no claims to the succession himself (with his own mini-history of taking kickbacks, according to Mujtahidd).

The defence ministry is also key because it offers those in charge a coercive force with which to project their power internally – externally, Saudi military hardware only really impresses countries within the orbit of the Gulf, not beyond, and the regime’s need for an external protector, once Britain, now the United States, remains paramount. But it is not the only institution with teeth: the other serious contenders for the succession after Salman (if he makes it) are Prince Mut’ib bin Abdullah, the king’s son, and Prince Mohammed bin Nayef, the deceased Nayef’s son, and while the former controls the National Guard, the latter controls the security forces. Now Salman’s family have consolidated their grip on the military apparatus of the defence ministry.

Abdullah needs to make sure he keeps the key grandsons happy to reduce the possibilities of internecine strife among them reaching dangerously public proportions. He needs to do this while making sure to advance subtlely the interests of his favourites in any future plan he may have: his recent appointment of Prince Mugrin as second deputy prime minister was a surprise but prepares the ground for a grandson to follow since Mugrin is the youngest of the surviving sons of Abdulaziz, and some surmise that the grandson he has in mind is his very own Mut’ib. Such a move towards a normative monarchical system could only be achieved with the utmost political skill and care and could risk provoking the very infighting he fears.

Interestingly, in the new political arena created by the Arab uprisings, there exists an opening for a contender to play the card of popular democrat. That was a possibility raised by Mohammed al-Mukhtar al-Shangiti, a Qatar-based Islamic studies professor who often appears on Al Jazeera, during a recent a conversation I had with him. “There are three princes with their own armies. One of them could adopt reform rhetoric to outdo the others if protests take off again,” Shangiti said. Shortly after that, one prince did in fact bring up the issue of reforms, entrepreneur Alwaleed bin Talal, who talked this month of at least partial elections to the Shura Council and increasing the quasi-parliament’s powers.

Alwaleed’s chances of being able to win family, or public, support for the top job are seen as extremely slim, but his comments came at a time of heightened tension as the interior ministry and religious authorities act in consort to try to crush more frequent and diverse examples of dissent across the board, on Twitter, on the streets, among Shi’ites, Sunni families of detainees and rights activists, some of whom have been tried, convicted and incarcerated. And his comments do point to a possible path for reforms to happen, via competing princes. Yet it is perhaps unlikely that anyone of the three key grandson princes with their hands on the levers of power is prepared to walk down that road without a qualitative shift in the nature of pressure from the street.