EXPLAINER - Why Thailand's judges are front and centre in its tumultuous politics

The two cases have heightened political uncertainty and raised concerns about potential upheaval in Southeast Asia's second-biggest economy, which has seen two decades of intermittent turmoil, with multiple parties disbanded and governments toppled by court rulings and military coups.

THE CASE AGAINST SRETTHA

Srettha faces dismissal after senators, who were hand-picked by a military junta, complained he violated the constitution by appointing to cabinet a former lawyer who was once jailed. The senators, whose terms have expired, said the appointment did not meet ethical requirements.

Pichit Chuenban, who represented the politically powerful Shinawatra family that founded Srettha's ruling Pheu Thai party, was found in contempt of court over an alleged attempt to bribe court staff, which was never proven.

Srettha denies wrongdoing and says Pichit, who has since resigned, was thoroughly vetted. Srettha's chief-of-staff told Reuters he expects him to survive the process.

WHAT IF SRETTHA IS DISMISSED?

Tycoon Srettha's case is among the factors that have increased uncertainty and roiled financial markets, compounding his struggle to revive the economy. Srettha has also faced delays in implementing his signature $12.8 billion handout scheme, and is facing falling popularity.

If he leaves, a new government must be formed and Pheu Thai would need to submit a new candidate for premier to be voted on by parliament, with no guarantees that they will succeed.

The vote could pit Pheu Thai against coalition partners, or lead to concessions in return for parliamentary votes, both of which could result in a shakeup of the governing alliance and a realignment of cabinet and policies.

WHO COULD BE PM IF SRETTHA EXITS?

Only those designated prime ministerial candidates by their parties before the last election can be nominated for premier.

They include Paetongtarn Shinawatra, Pheu Thai leader and daughter of influential billionaire Thaksin Shinawatra, former Justice Minister Chaikasem Nitisiri, Interior Minister and deputy premier Anutin Charnvirakul, Energy Minister Pirapan Salirathavibhaga and Prawit Wongsuwon, an influential former army chief who was involved in two coups.

WHAT HAPPENED TO MOVE FORWARD?

The Constitutional Court on Aug. 7 disbanded Move Forward over its campaign to amend a law on royal insults that protects the monarchy from criticism. Its 11 party executives received 10-year political bans.

Judges said it improperly used the royal family to gain an election advantage, putting the palace in conflict with the people. The party, which was ordered to cease the campaign by the same court in January, maintains it has not undermined the crown, but wanted to stop the law from being abused.

Move Forward won most seats in the last election but was blocked from forming a government by lawmakers allied with the royalist military. Its dissolution was criticised by major Western powers.

HOW HAS THE PARTY RESPONDED?

The surviving 143 Move Forward lawmakers on Friday formed a new vehicle, People's Party, which will be the biggest in parliament. It is led by Natthaphong Ruengpanyawut, 37, a cloud software executive who was involved in a digital campaign strategy that won Move Forward massive support.

Natthaphong has promised the same platform and, controversially, to revive the campaign to reform the law on royal insults, but address the issue with caution.

HOW WILL IT BE RECEIVED?

People's Party will likely inherit and try to build on Move Forward's huge urban and progressive base, making it a formidable force for the next election.

But it is certain to clash with Thailand's old elite among the conservative establishment, the royalist military top brass, and wealthy families that benefit from the business monopolies Move Forward sought to dismantle.

People Party's biggest opponent could be the judiciary, which has repeatedly ruled against its predecessors. Its stance on the royal insult law - a taboo issue - could limit its ability to form alliances and gain bipartisan support for other legislation.