The next round of voting for a prime minister is likely to take place on Tuesday after the Constitutional Court on Wednesday dismissed the Ombudsman's petition on the rejected renomination of Move Forward Party (MFP) leader Pita Limjaroenrat.
The court's unanimous decision is seen as clearing the way for the process to select a new leader to proceed. The selection was on hold pending the court's ruling on parliament's decision on July 19 to reject Mr Pita's renomination.
Citing the court's decision, parliament president Wan Muhamad Noor Matha said on Wednesday that parliament's rejection of Mr Pita's renomination is considered valid but parliament's legal team will meet on Thursday to study the court's decision.
He would then meet parties and senators to discuss the vote.
He said a prime ministerial candidate is not legally required to outline his vision before parliament although some senators have demanded Pheu Thai's Srettha Thavisin to do so and address questions they may have.
The two prime ministerial candidates on offer in 2019, Gen Prayut Chan-o-cha and Thanathorn Juangroongruangkit, did not present their vision before the vote, said Mr Wan.
In dismissing the petition brought via the Ombudsman, the court said the three petitioners were not directly affected by parliament's decision. The complainants were Pornchai Theppanya and Boonsong Chalaythorn, who both voted for the MFP in the May 14 general election. Another complainant was MFP MP Panyarut Nuntapusitanon.
They said parliament's rejection of Mr Pita's renomination affected their constitutional rights. They also sought a court order for parliament to put off the vote pending its ruling.
However, the court said the prime minister is selected under Section 272 and Section 159 of the charter and any candidate put forward must be nominated under Section 159.
In this case, the three petitioners were not named as prime minister candidates by any party and were not nominated for the vote in parliament either, so their rights were not directly affected.
Shortly after learning of the ruling, Mr Pita said he would not a file a fresh petition with the court because he believed the matter should be settled by parliament, not the court.
MFP MP Rangsiman Rome said the party would submit a motion asking parliament to review its rejection of Mr Pita's renomination again.
He said the party's move was not an attempt to create political trouble and he expected parliament to correct its mistake.
"This is a matter of principle. We're not doing it for our own gain or to have Mr Pita renominated.
"A prime minister candidate, regardless of the party, will benefit from this motion except those who have a hidden agenda," he said.
With the prime minister voting coming up, Bhumjaithai Party leader Anutin Charnvirakul reiterated on Wednesday that negotiations over the allocation of cabinet seats should take place before the vote.
He denied reports the party and Pheu Thai could not reach an agreement on the distribution of positions, but said the party should be allowed to continue working in ministries it holds now for the sake of continuity.
Meanwhile, the court Wednesday also gave the MFP and its leader another 30 days to give a statement in a case that could lead to the party's dissolution.
The case was filed by Theerayut Suwankesorn, a lawyer well known for his defence of Suwit Thongprasert, an ex-activist monk formerly known as Phra Buddha Isara.
Mr Theerayut asked the court to rule if the MFP's policy on Section 112 of the Criminal Code, better known as the lese majeste law, was an attempt to overthrow the constitutional monarchy.