Thailand has in the past decade been increasingly unsettled by a sequence of political upheavals, with two military coups since 2006. In the first, prime minister Thaksin Sinawatra was overthrown; in the second, his sister Yingluck was ousted.

The coups triggered a wave of protests and the emergence of two factions: the mostly rural supporters of the Shinawatras – known as “red shirts” – and their Bangkok-based detractors more closely aligned to the monarchy – known as “yellow shirts”.

The military government that replaced Yingluck last year has since cracked down on dissent, with an increasing number of people arrested and charged with breaking the lese-majeste laws, which prohibit any criticism of the monarchy.

“One of the main reasons for the political turmoil that we have seen in Thailand over the past 10 years has been the secret succession struggle,” said Andrew MacGregor Marshall, author of A Kingdom in Crisis: Thailand’s Struggle for Democracy in the Twenty-First Century.

One key reason for the intense speculation over the succession, Marshall said, is that the country has the richest monarchy in the world, with an estimated wealth of US$35 billion – perhaps even more. Under the current monarchy, the king allows the money to be spent by other palace elites.

“Whoever becomes the next monarch would be in control of that money,” Marshall said. “The elites are really worried after the king dies they may lose control of the money. This is why the succession is contentious and has been contested.”

There have been doubts over whether the heir-apparent, Crown Prince Maha Vajiralongkron, is in a position to replace his father, largely due to concerns over his private life and temperament. As a result, some have suggested his sister, Princess Sirindhorn, warmly regarded by the Thai people, would be a more popular ruler.

However, some observers suggest the succession may be smoother than expected, with the crown prince inevitably ascending the throne.

“This is really the only immediate scenario,” said Dr Paul Chambers, director of research at the Institute of South East Asian Affairs in Chiang Mai.

Once distrusted by the military, the crown prince has more recently been able to earn their vital support, according to Professor William Case from the City University of Hong Kong, with ruling junta’s recent crackdown designed to ensure a smooth transition from father to son.

“And once the transition does take place and the new king is on the throne, that would lend more legitimacy to the military, which is why the military struggles and fights so hard to control the monarchy and ensure the smoothness of the succession,” Case said.

Still, in the post-succession era, the country could yet face further upheaval, with the political divide between the red-shirts and the yellow-shirts never far from the surface. And, in the meantime, any anti-junta demonstrations would likely provoke an even stricter crackdown from the military, said Chambers, who also questioned whether the military might decide that “having tasted power, it wants to remain in charge for a longer period of time”.

In the past week, two high-profile instances of official censorship have drawn attention to these controls on political speech, with two articles in the international edition of The New York Times removed by the local printer in Thailand. The first article was a discussion of the country’s failing economy and the second was a piece examining the workings of the Crown Property Bureau.

According to Case, the struggling economy could emerge as yet another wildcard in the country’s ongoing political drama: “When ordinary people start to suffer, when the middle-class see their living standard starts to decline, when you’ve got this kind of pressure and these kind of tensions, it can rekindle new kinds of mass level discontent.”