A last-ditch effort to settle the wrangle over the calculation of list-MPs will succeed on Monday provided the quorum is met, said Sathit Pitutecha, chair of the parliamentary panel scrutinising the organic bill that governs the calculation method.
Parliamentarians are bound by a common legislative duty to work to pass a law. The fate of the list-MP calculation formula in the draft of the organic bill on the election of MPs rests with the joint sitting in parliament, he said.
Lawmakers were split over whether to use the number 100 or 500 in calculating how list MPs are allocated.
The 100 divisor, reflecting the number of seats up for grabs in the party-list system, is favoured by larger parties, while 500, which refers to the number of MP seats at stake in both the constituency and list systems, allows smaller parties a better chance of winning list MPs.
Parliament voted earlier to adopt 500 as the divisor, which upset larger parties that had their hearts set on 100. The vote prompted the scrutiny committee to rework the amendment draft it had already scrutinised in order to comply with the use of 500.
However, the amendment process was far from over as joint meetings of MPs and senators to deliberate the bill on July 27, Aug 3 and this Wednesday all collapsed due to the lack of a quorum.
Some lawmakers were suspected to have deliberately skipped the meetings in a bid to let the deadline for passing the amendment -- which falls on Monday -- lapse without parliamentary endorsement.
That would effectively block the change to the way party-list seats are calculated.
According to legal experts, if the bill is not endorsed within the 180-day deadline, as required by the charter, the original version, sponsored by the cabinet and drafted by the Election Commission (EC), will be considered approved by parliament.
The EC draft stipulates the adoption of 100 as the divisor.
Earlier, Somchai Srisutthiyakorn, a Seri Ruam Thai Party member, said he would petition the National Anti-Corruption Commission to investigate if there have been any ethical violations over the three collapsed meetings.
Parliament president Chuan Leekpai has called a special joint sitting of MPs and senators to be held on Monday, the last chance for lawmakers to review the amendment of the bill.
On Friday, Mr Sathit, who is also the deputy public health minister and a Democrat Party MP, insisted that if the quorum was achieved, the amendment would likely clear parliament.
He admitted some MPs think the amendment should be dropped to revert to the EC-initiated draft that supports 100. They felt that would better cater to the interests of the public.
On Monday, individual MPs are free to vote on the amendment, Mr Sathit said, adding most coalition parties have now agreed to go back to using 100.
Mr Chuan declined to say on Friday if the amendment would be approved during Monday's meeting.
He said the Senate has put off its regular meeting so a joint sitting could place to thrash out the amendment bill for the last time.
Deputy Democrat leader Ong-art Klampaiboon said the party refused to be part of a ploy to wreak havoc in parliament in order to advance anyone's agenda, even though it was meant to bring back the use of 100, which the party supports.
The party's MPs have all vowed to attend the meeting, he said.
Somkid Chuakong, a Pheu Thai Party MP for Ubon Ratchathani and opposition deputy chief whip, said the party planned to announce why accepting 500 would contravene the constitution and therefore should be considered unacceptable.