So who wields influence now?
Analysis: Power still with the 3 'brothers', writes Wassana Nanuam
The passing of Privy Council president Gen Prem Tinsulanonda is unlikely to diminish the political power wielded by the "three military brothers" led by Prime Minister Prayut Chan-o-cha, according to a military source.
One reason is that Gen Prem had not been active politically lately. Most of the power lies in the hands of Gen Prayut and the other two key "brothers" -- Deputy Prime Minister and Defence Minister Gen Prawit Wongsuwon and Interior Minister Gen Anupong Paojinda -- of the elite Burapha Phayak, or "Tigers of the East" clique.
When Gen Anupong was appointed army chief after the 2006 military coup, the order of succession in the army was designed in such a way that officers loyal to him would occupy important posts.
After three years, Gen Anupong passed the baton on to Gen Prayut, who would become the army's commander-in-chief for four years, before he was installed as premier following the 2014 coup.
The majority of the military's most powerful units are commanded by officers from cliques such as Burapha Phayak and Wong Thewan to ensure an even distribution of power and prevent internal conflicts, according to the source.
The deep respect Gen Prayut, Gen Prawit and Gen Anupong had for Gen Prem turned the statesman into a figure of prominence, said the source.
However, the source noted that after Gen Prem retired a long time ago from the army, he was no longer well-acquainted with the leaders of the armed forces, who were from younger generations.
Gen Prem also had little influence on the outcome of military post reshuffles, as most posts were eventually filled by those directly linked to Gen Prayut, Gen Prawit and Gen Anupong, as well as generals from other cliques, the source said.
It was viewed as customary for the three generals and the armed forces leaders to call on the late statesman at his Si Sao Thewes residence on his birthday, and at New Year and Songkran to seek his blessings.
Strategically, it was an astute way of showing that they were on the same page and allied with Gen Prem, who in turn publicly supported the Prayut government and the National Council for Peace and Order, the source said.
With Gen Prem's passing, all eyes are now on Gen Surayud Chulanont, a former prime minister and army chief. Gen Prem had asked Gen Surayud -- also a Privy Council member -- to act on his behalf as he increasingly suffered from ill health.
Gen Surayud is also chairman of the Ratthaburut Foundation, founded by Gen Prem, the source said.