Sonthi will retire as Army commander-in-chief at the end of September and quit as chairman of the Council for National Security (CNS) when an elected government assumes power after the national poll, expected to he held in December.
Sonthi has defended his "goodwill" in staging the September coup saying the abrupt interference was to overthrow the malaise of the full-scaled capitalist and corrupt government of Thaksin Shinawatra. He insisted he had no intention to retain power or become prime minister.
However, Sonthi came under fire from critics and allies alike on Sunday for playing games over a return to power by the people.
It follows fresh speculation he will run in the next general election with a new political party backed by the military.
Some key members of the defunct Thai Rak Thai Party, recently banned by the Constitution Tribunal from the electoral process for five years, are believed to involve in building a haven for Sonthi.
The CNS chief is the only man apparently attempting to seek an amnesty for the 111 Thai Rak Thai executives punished by the ban. However, he unwillingly stepped back after public opposition.
Pinit Jarusombat, Suwat Liptapanlop and Preecha Laohapongchana, who have formed a Thai Rak Thai splinter group, are said to be planning to register a Rak Chat (Patriotic) party with backing from General Winai Phattiyakul, one of the CNS leaders.
Rak Chat, it is speculated, will guarantee a "safe landing" for Sonthi after an elected government assumes power.
Whether Sonthi wants it or not, it is clear the only way to ensure his safe departure is to rely on himself.
Sonthi will leave his Army post in October. Although Sonthi will still head the CNS, things will become fragile and insecure for a coup leader no longer in direct control of the Army.
Above all Sonthi wants to ensure Thaksin and his clan has no chance to seek revenge. Thus, he is believed to handpicking his successor. General Winai and General Montri Sangkasab are favourites at this point.
However, Sonthi knows he cannot trust politicians. They will switch sides at any time to protect their benefits. Hence, nothing can guarantee the upper hand in the game of power like being in control.
In contrast to his denial over an intention to reign post-CNS Thailand, Sonthi is seen to be kicking off a campaign to become the next prime minister.
He has co-chaired Cabinet meetings with Prime Minister Surayud Chulanont for months, in a bid to learn his future job as prime minister.
Sonthi has travelled to provinces to convince local officials they will be treated better under his rule in exchange for their "cooperation" in cutting links with Thaksin and anti-CNS politicians.
On some weekends, Bangkok shoppers are surprised by Sonthi's unexpected visits to Chatuchak or Banglampoo markets, which he says are to see how well his people live.
While keeping power-thirsty politicians guessing if he and other CNS leaders will cling to power, he recently led a campaign encouraging youth to help save the planet.
A day after the coup, Sonthi and his generals promised to remain in power for the two weeks it took to install a civilian government.
In fact, they transformed themselves into the most powerful body in the Kingdom. The CNS duplicated the 1991 National Peacekeeping Council. Its first step was to "whitewash" itself and divert public attention from its intentions by renaming itself the CNS in the interim charter.
Sonthi insists he will not cling to power. However, some allegedly corrupt politicians are now on the campaign for the forthcoming poll while the coup leaders are on their way to a "safe landing".
History proves they will find a winning combination in the end.
By Weerayut Chokchaimadon