On Jan 6, Saudi Arabia's King Abdullah tried to reassure the world that his country is prepared to absorb the economic shock of plummeting oil prices and to deal with worsening conflict in its two neighbours, Iraq and Yemen.
But the monarch, who has been hospitalised since Dec 31 for pneumonia, could not deliver his annual "state of the kingdom" address to Saudi Arabia's consultative council.
Instead, Crown Prince Salman delivered the speech on the king's behalf. That image - of an ageing heir with his own health troubles standing in for a 90-year-old king - did little to ease concerns about whether King Abdullah is still fit to lead, and address larger questions over the line of succession in one of the world's most important oil producers.
Prince Salman, 79 and a half- brother of the king and his designated successor, has taken on a larger public role in recent months, standing in for the king at a summit meeting of Persian Gulf leaders in Qatar last month.
But Prince Salman himself is in poor health, and reportedly suffers from dementia. If King Abdullah dies or is incapacitated, and Prince Salman ascends to the throne, he might not be king for long. It's also unclear who Prince Salman would designate as his crown prince - and that crucial decision could destabilise the royal family.
Prince Muqrin, 69, who has served as head of Saudi intelligence and in other senior positions, was installed last year by King Abdullah into the newly created post of deputy crown prince, making him second in line to the throne.
But any new king has the right to choose his own crown prince. If Prince Muqrin is passed over by Prince Salman, that could set off a succession battle within the House of Saud at a time of regional crisis and instability in the global oil markets.
Beyond Prince Salman's expected ascension to the throne, the Saud dynasty faces a larger challenge over succession within its system of hereditary rule. The kingdom was founded in 1932 by Abdulaziz al-Saud, and he left behind a system where the throne is passed from older son to younger son (the king had 35 surviving sons when he died in 1953).
With the old generation of Abdulaziz's sons dying off, the kingdom has no clear plan to hand power to the "new" generation of royals - Abdulaziz's grandsons, of which there are at least 30 who could be in line for the throne.
Prince Muqrin is the youngest surviving son of Abdulaziz who is still in the running for the throne (he has several older siblings who have been passed over). If he becomes king, he would appoint a crown prince who would have to come from the third generation of royals. Prince Muqrin does not have strong enough support within the royal family to appoint one of his sons to the post.
One theory is that King Abdullah positioned Prince Muqrin as second in line so that he would be beholden to the king's sons, one of whom could become king once the generational shift takes place.
Aside from the king's illness and questions over succession, Saudi Arabia is faced with a series of regional and economic threats.
Most prominently, the kingdom must cope with plunging oil prices. On Jan 7, Brent crude, the international benchmark, fell below US$50 a barrel for the first time since May 2009 - a drop caused in part by Saudi Arabia's refusal to cut high production levels. At the last Opec meeting in late November, the Saudis led the charge to prevent the cartel from cutting production, which would have driven prices up. Instead, the kingdom is trying to gain more control over the global market, and to drive out US shale oil, which requires higher prices to remain competitive.
So far, Saudi leaders have been able to withstand the economic shock by increasing oil production to make up for falling prices, or by accessing some of the kingdom's US$750 billion (S$1 trillion) stashed in foreign reserves. But that is not a long-term solution.
Saudi Arabia is also engaged in proxy battles with its regional rival Iran in several arenas: Syria, Iraq and Yemen. The kingdom is using oil as a weapon to punish Iran for its support of President Bashar al-Assad's regime in Syria. Facing Western sanctions and economic isolation, the Iranian regime is dependent on oil remaining at US$100 a barrel or more to meet its budget commitments.
Any new leader is unlikely to change the larger contours of Saudi foreign policy - or the kingdom's use of oil to protect its interests and try to keep Iran at bay. But the new king will face decisions on succession that could reshape the monarchy's future.
The writer is a journalism professor at New York University and a former Middle East bureau chief at Newsday, a daily newspaper in New York State, America.