Parliament confirmed Friday it would vote again for a new prime minister next week, after military-appointed lawmakers foiled liberal frontrunner Pita Limjaroenrat's bid for the top job.
Mr Pita's Move Forward Party (MFP) won the most seats in May elections, buoyed by young people eager for progressive reforms after nine years of army-backed rule in the kingdom.
But the Harvard-educated millionaire's campaign to lead the next government was knocked back Thursday by the legislature's senators, who consider his pledge to reform strict royal defamation laws a red line.
And the vote came just a day after Thailand's top election body recommended the Constitutional Court suspend Pita as an MP -- providing more fuel for senators already poised to vote against him.
Parliament will hold its second ballot for a new prime minister on July 19, deputy house speaker Pichet Chuamuangphan told AFP on Friday.
But it remained unclear whether Mr Pita would be renominated or if he would face any additional candidates.
"We still have to talk about it first," said Mr Pichet, a member of MFP's coalition partner Pheu Thai. "For now, it's gathering opinions and feedback from the people."
Mr Pita has insisted that he remains a candidate to lead the next government and was "not giving up" despite taking only 324 votes overall -- well short of the 375 needed.
Just 13 senators voted for him, with many voicing their opposition to MFP's pledge to soften the royal defamation laws.
- Senate hurdle -
All 250 senators were appointed under the junta-drafted constitution, which political analyst Thitinan Pongsudhirak said was a reliable impediment to MFP's reformist platform.
"It is a way for the authority and the regime to stay in power in the long term and to prevent a pro-democracy government that can stand against them," he told AFP.
Mr Thitinan said he expected Pheu Thai -- a party that held office before a 2014 military coup but is now in an uneasy alliance with MFP -- to field prime-ministerial candidates of their own.
If a Pheu Thai candidate won with the backing of conservative lawmakers, they may yet form a government that excludes Pita's party altogether, he added.
"The conservative forces see Pita and MFP as a threat to be put down," he said. "I would not be surprised, along these lines, that they would do the same thing to prevent MFP from even being in the government."
Pheu Thai secretary-general Prasert Jantararuangtong said the party would meet with the MFP on Friday evening to discuss strategy for the next ballot.
"We need to discuss what we do next," Pheu Thai leader Cholnan Srikaew said.
Speaking to reporters, he referenced the parties' coalition agreement supporting Pita for PM, and said: "I am still backing that statement."
- 'Abuse of power' -
Mr Pita rode a wave of support that saw voters emphatically reject almost a decade of army-backed rule under Prayut Chan-o-cha, who took power in the 2014 coup.
But the MFP's reformist agenda has drawn strident objections from conservative supporters of the country's establishment, particularly its plans to shake up the outsized economic role of powerful business monopolies.
On Wednesday, the electoral commission recommended Mr Pita's suspension from parliament over allegations he broke campaign rules -- a move the MFP branded as an "abuse of power".
The recommendation followed a probe into Mr Pita's ownership of shares in a media company, which MPs are prohibited from under Thai law.
The station has not broadcast since 2007, and Pita has said the shares were inherited from his father.
The MFP was the only party that campaigned on tackling the thorny issue of the royal defamation laws, but that too landed it in trouble.
The Constitutional Court has agreed to hear a case alleging that the promise amounts to attempting to "overthrow" the constitutional monarchy.
The party has two weeks to present its defence.