The opposition has expressed concerns that the stalled charter amendment could become a pawn in a trade-off deal between coalition partners.
Such concerns were conveyed during a House meeting by Parit Wacharasindhu, a PP list MP and a party spokesman.
Mr Parit spoke during an interpellation that he filed, which was directed at Prime Minister Paetongtarn Shinawatra. However, the premier was absent from parliament attending official engagements and assigned her deputy, Prasert Jantararuangtong, also the digital economy and society minister, to fill in for her.
Mr Parit demanded answers as to why a coalition party, a reference to Bhumjaithai, and many senators have refused to support the charter rewrite bid.
This comes after two successive House meetings last Thursday and Friday, which were scheduled to have a vote to admit Section 256 for amendment, collapsed. The section was designed to open the door to forming a Constitution Drafting Assembly (CDA), marking a prelude to a rewrite of the entire charter.
However, Bhumjaithai vocally opposed tampering with Section 256, fearing it would cause a legal backlash. According to a previous Constitutional Court interpretation, establishing a CDA amounts to a wholesale charter rewrite, which requires a referendum to be held first.
Prasert: Notes differing views
The proposal to amend Section 256 was halted by Pheu Thai's push to seek a Constitutional Court ruling on whether parliament has the authority to change Section 256 for the purpose of starting a charter amendment.
On Thursday, Mr Parit said that even though Bhumjaithai has pledged to cooperate with the charter amendment when the court ruling is made, there is no telling whether the majority "blue" senators will go along with the charter rewrite. Blue is the colour of Bhumjaithai.
He also said Ms Paetongtarn had insisted she had discussed the charter rewrite proposal with coalition parties. However, Bhumjaithai leader Anutin Charnvirakul has come out to deny this.
The PP MP noted that the coalition parties were not on the same page regarding the entertainment complex draft bill, which was controversial due to the inclusion of casinos.
Mr Parit pressed for clarity over whether the draft bill, sponsored by Pheu Thai, is stalling the charter amendment to satisfy Bhumjaithai in exchange for the latter's support over the entertainment complex project.
"My question to the prime minister has to do with how coalition parties could come around and get behind the entertainment complex draft bill without any kind of a backdoor agreement being struck," he said.
Mr Prasert, meanwhile, maintained that Pheu Thai was sincere in amending the charter. The request for the Constitutional Court's ruling over proposed changes to Section 256 was to ease the minds of lawmakers who fear a legal backlash to meddling with the section without a prior referendum.
The coalition parties are ready to back the modification of Section 256 once a ruling is given.
Coalition partners had differing views on the issue, which is their privilege, but they are not disunited, Mr Prasert said.
He added the two bills pertaining to the modification of Section 256 are sponsored by Pheu Thai and PP. He said it would be unfair not to seek the court's ruling and let the coalition parties face potential legal consequences.
He said the draft entertainment complex bill was being vetted by the Council of State, the government's legal arm, and has not reached parliament.
He added that the government regards all major policies, from the entertainment complexes to charter amendment, as equally important.