Deputy Prime Minister Gen Prawit Wongsuwon will step into the hot seat should Gen Prayut Chan-o-cha complete his eight-year term in office in August, Deputy Prime Minister Wissanu Krea-ngam told reporters on Monday.
Mr Wissanu was responding to a question about the possibility of a nayok samrong ("PM in reserve") which surfaced last week following an interview given last week by Gen Prawit about the Palang Pracharath Party's (PPRP) prime ministerial candidates in the next election.
Mr Wissanu, a legal specialist, said he had not heard the term nayok samrong used in such a context before, but pointed out that there would be nothing unusual about Gen Prawit, who is "next in line", becoming the acting prime minister if Gen Prayut has no choice but to vacate the position in August.
Should a new prime minister need to be selected, parliament president Chuan Leekpai will call a vote with the replacement chosen from lists submitted to the Election Commission (EC) by parties ahead of the March 2019 general election.
This means parliament would decide between former Democrat leader Abhisit Vejjajiva, Bhumjaithai leader Anutin Charnvirakul, and Chaikasem Nitisiri, Chadchart Sittipunt and Khunying Sudarat Keyuraphan, who were on the main opposition Pheu Thai Party's prime ministerial candidate list, Mr Wissanu said.
Prawit: Would step into the breach
When asked about the possibility of an outsider under Section 272 of the constitution, Mr Wissanu said it could happen but the process is rather complicated.
"Half of the MPs must initiate a motion to suspend the rule requiring all candidates be selected from the lists. The motion then needs to be approved by 500 members from the House of Representatives and the Senate to proceed," he said.
Last week, Gen Prawit, leader of the ruling PPRP, said the party may come up with alternative candidates for prime minister in the next poll when asked if the PPRP was certain to nominate him alone.
The PPRP leader's answer -- "I don't know yet. Maybe" appeared to have triggered talks about a nayok samrong while the idea of an outsider prime minister was discussed by Gen Wit Devahastin na Ayudhya and Capt Thamanat Prompow, leader and secretary-general of the Setthakij Thai Party.
The issue of when Gen Prayut's tenure must end has yet to be settled after a legal team from the House of Representatives claimed that he is entitled to serve as premier until 2027.
However, critics argue the clock started ticking when he took over in a coup as the head of the National Council for Peace and Order (NCPO) in August 2014.
The constitution places an eight-year limit on any one person holding the position, regardless of whether terms are served back-to-back.
The Pheu Thai Party is expected to ask the Constitutional Court to rule on Gen Prayut's term in coming weeks.