The Constitution Drafting Committee (CDC) has insisted it will stick to the proposed mixed-member apportionment electoral system (MMA) despite criticism from political parties and academics.
CDC chairman Meechai Ruchupan said Thursday the committee had decided the MMA system will be adopted in the new constitution.
Under the proposal, the House of Representatives will comprise 500 members, with 350 constituency MPs and 150 party-list MPs, compared to the previous election system under the 2007 charter with 375 constituency MPs and 125 from party lists.
A single ballot will be used for both constituency and party-list MPs, Mr Meechai said. All votes cast for the losing constituency candidates will be used to calculate the number of party-list seats, rather than being thrown away under the old first-past-the-post system.
Mr Meechai said another key feature of the system was that if a winning constituency MP candidate is later disqualified for breaking the election law, the votes cast for the winner will be subtracted from the party-list votes of the winner's political party.
He said the Election Commission must first endorse all winners in constituency elections within 30 days of the election so the figures can be used to calculate the number of party-list seats.
If any poll winners are later found guilty of violating election laws, they will be disqualified. Then, poll re-runs will be held and the results will be used to recalculate party-list seats nationwide, he said.
The shift in the number of constituency MPs could have a significant impact on the formation of a government after the election, Mr Meechai said.
"It could cause uncertainty, which may tilt the balance of power among political parties jockeying to form a government. But if the candidates are guilty of committing poll fraud, they should not be let off the hook despite the uncertainty," Mr Meechai said.
The best way would be to avoid breaking election laws, he said.
The MMA system means that if poll fraud takes place in just a single constituency, then the number of votes for party list-MPs cannot be counted until after a poll re-run is completed and the result is announced.
Mr Meechai also said a single ballot was a sensible choice as it allows voters to consider both individual candidates and the political parties which field them. The MMA system will encourage political parties to choose the best candidates to contest elections, he added.
The proposed system is also fair to voters as their votes for unsuccessful candidates will not be discarded and will be used in the count of party-list MPs, he said.
"As a result, people will be more eager to vote. The CDC is doing this for the benefit of the people, not for the sake of political parties," Mr Meechai said.
The chairman also insisted that "no" votes must count, saying constituency MP candidates must win more votes than the number of "no" votes. He said the CDC will determine how many poll re-runs should be held if a candidate collects fewer votes than the "no" votes.
Mr Meechai said the CDC was also seeking ways to ease the impact on the vote count for party-list seats nationwide if a constituency candidate gains fewer votes than the "no" votes.
Also on Thursday The Pheu Thai Party again issued a statement opposing MMA and the single ballot system. It said the new voting system must ensure political parties have an equal chance of fielding candidates to respond to the needs of voters.
The single ballot system cannot demonstrate whether a voter intends to vote for a candidate or a party, Pheu Thai added. The system restricts voters' rights and does not reflect their intentions as it does not allow them to make their choice freely, it said.
Pheu Thai also argued that a political party with many winners in constituency elections would not necessarily win a majority of seats in the House of Representatives as it would have all its party-list votes taken away.
The MMA system would not guarantee that vote-buying will be reduced as only legal measures can curb poll fraud, the party said.
"The Pheu Thai Party believes MMA is not a universal voting system and is not suited to Thai politics. It will create more problems than solutions," the party said.
Prime Minister Prayut Cha-o-cha on Thursday lashed out at critics of the proposed voting system, saying most of those who opposed the new rules were politicians.
"The new system will make it more difficult for them to come to power so they want the same old system to give them more votes just like before," Gen Prayut said.
