Pheu Thai heavyweights stood firm on the party's push to amend the charter, insisting public participation must remain central to drafting a new constitution.
The stance came after the Bhumjaithai Party (BJT) withdrew support for Pheu Thai's amendment bill over legal concerns, prompting Pheu Thai leader Julapun Amornvivat to announce a review of the proposal. The move raised concerns among some party members that the party could retreat from its position.
Mr Julapun on Friday acknowledged the need for broader backing, noting that charter amendments require majority support in parliament and approval from at least one-third of senators.
List-MP Chaturon Chaisaeng said in a social media post that the latest draft was largely unchanged from the party's previous proposal and remained consistent with commitments made during the election and referendum campaign.
He said the drafters had carefully considered Constitutional Court rulings and were confident the bill did not conflict with them.
Under the proposal, the public would not directly elect constitution drafters but would take part in an initial selection process, with parliament making the final decision, he said.
Mr Chaturon said the model would broaden public participation and help produce a constitution that better reflected public wishes, rather than leaving decisions solely to parliament.
He also urged party executives to clarify the proposal to the BJT and address its concerns, while calling on fellow Pheu Thai MPs to preserve what he described as a key campaign pledge.
He added that parties could support all amendment proposals at this stage, with details to be debated during committee scrutiny and subsequent parliamentary readings.
List-MP Adisorn Piangkate criticised the BJT, saying it had shown little genuine commitment to charter reform from the outset.
He urged Pheu Thai not to be dictated to by its coalition partner, saying he trusted legal expert Chousak Sirinil and was confident the bill complied with court rulings.
Meanwhile, People's Party list-MP Parit Wacharasindhu said all charter amendment proposals should be endorsed in principle during the first reading and examined in committee.
"I hope this is not an effort to ensure that only the BJT's draft survives the first reading," he said.
Democrat leader and list-MP Abhisit Vejjajiva expressed surprise at the BJT's position, saying Pheu Thai's bill resembled an earlier version the BJT had previously backed in principle.
He said a House committee planned to seek clarification from the Constitutional Court on the requirement that constitution drafters must not be "directly elected".
"That should help resolve the issue," he said.
