All eyes are on two small parties which are expected to help the ruling Palang Pracharath Party (PPRP) secure party-list seats and counteract a new method of calculating the seats seen to favour small parties at the expense of big ones.
The Ruam Thai Sang Chart Party and the Palang Thai Chaichana Party are expected to serve as the PPRP's offshoots to support the PPRP in the next poll, observers said.
Key figures of the parties are known to be close associates of Prime Minister Prayut Chan-o-cha and Deputy Prime Minister and PPRP leader Prawit Wongsuwon.
The move comes after a total of 354 MPs voted for the 500 method to calculate party-list seats on July 6.
Most of the 354 votes were from coalition parties -- Palang Pracharath, Bhumjaithai, the Democrats and six small coalition parties.
The question splitting lawmakers was whether 100 or 500 should be used to calculate the number of list MPs in the next polls.
Wit: Seen as likely leader
The figure 100 derives from the total number of party-list MPs while 500 would include all of the constituency MPs as well.
Under the amended constitution, there would be 400 constituency MPs in the Lower House, up from the current 350, and 100 party-list MPs, down from 150, in the next poll.
While legal experts and some MPs and senators had argued against using the larger number, smaller parties and a growing number of legislators stood firm that this should be adopted.
Small parties would find it easier to win a list seat using that method. But Pheu Thai has been a staunch supporter of the smaller number as it was confident of capturing many of the 100 seats up for grabs in the party-list system. Other large parties including the PPRP and the Democrats, a coalition member, also previously backed the use of 100 seats.
However, coalition parties made an about-turn and agreed to support the use of 500 after it received the green light from Gen Prayut in what is seen as a bid to prevent Pheu Thai from winning a landslide in the next poll, sources said.
''The political situation is changing. Chadchart Sittipunt won a landslide in the Bangkok governor election while the opposition's candidates won many seats in the Bangkok council election, but the PPRP won only two seats,'' the sources said.
''There has been concern about the emergence of Paetongtarn Shinawatra, the youngest daughter of ex-premier Thaksin Shinawatra, as Pheu Thai's candidate for the premiership, with speculation the party will win a landslide. Several opinion surveys also suggested Gen Prayut's popularity was waning,'' the sources said.
In light of this, Gen Prayut and Gen Prawit had to resort to that calculation method to stop Pheu Thai. Under this calculation method, Pheu Thai could not win a single party-list seat in the 2019 election, the sources said.
Therefore, the two small parties are needed to support the PPRP in the next poll. The Ruam Thai Sang Chart Party was founded by Seksakol Atthawong, a former aide to the PM, to support Gen Prayut if he wishes to vie for the same role at the next poll.
Pirapan: Tipped to head his party
It received public attention early last year, after claims surfaced that the party was set up as an alternative to the PPRP, should it encounter legal trouble. The party will meet early next month amid speculation that former Democrat Pirapan Salirathavibhaga will be named party leader.
Palang Thai Chaichana Party will also meet next month to elect executives, with Gen Wit Devahastin na Ayudhya, former leader of the Setthakij Thai Party, expected to be chosen as its leader.
Gen Wit was forced to resign as Setthakij Thai leader following a rift with Capt Thamanat Prompow who is known not to be on good terms with Gen Prayut. The party executive board then proceeded to pick Capt Thamanat as leader, which frees him to oppose the government if he so chooses.
The conflict between the pair thwarted the plan to use Setthakij Thai as a splinter party of PPRP so the two parties mentioned above have stepped in to fill the shoes instead, the sources said.