Thailand's Constitutional Court is set Wednesday to decide whether to remove Prime Minister Yingluck Shinawatra from office on abuse of power charges, a ruling that threatens to plunge the kingdom further into turmoil.
The premier appeared at the court on Tuesday to deny allegations that she replaced the national security chief in 2011 for the benefit of her party - an offence for which she can be sacked.
But the court, which has played a key role in recent turbulent chapters of Thai politics, said it was ready to rule at noon on Wednesday.
The case, one of two potential knockout legal moves against Yingluck's premiership, comes as Thailand's prolonged political crisis reaches a critical juncture.
Anti-government protesters are still massed on Bangkok's streets - although in diminished numbers - and Yingluck's "Red Shirt" supporters are also threatening to rally to defend her.
If she is dismissed then a deputy prime minister can replace her until a new government is formed through elections.
But observers say it is possible the court will also rule against her cabinet for endorsing the decision to transfer security chief Thawil Pliensri, who has since been re-instated.
Sacking Yingluck and her cabinet could send the kingdom into uncharted territory, leaving the nation without a premier, cabinet and lower house - which was dissolved to hold elections in February that were later annulled.
Yingluck appears trapped by legal moves against her premiership after six months of street protests that have left 25 people dead and hundreds wounded in gun and grenade attacks.
"Prime Minister Yingluck is their (the protesters') obstacle in overthrowing democracy," Red Shirt chairman Jatuporn Prompan said on Tuesday.
"I expect the verdict will not be good for the government.... I heard they want to sack the entire cabinet," he said.
An anti-government protester waves the national flag during a march through streets in Bangkok. Protesters are attempting to oust the government of Prime Minister Yingluck Shinawatra. Photo / AP
His group have vowed to come out on the streets if Yingluck is toppled, kindling fears of looming clashes between rival political sides.
The Reds say they are unarmed, but have held several training camps in their rural northeastern heartlands for guards to protect their future rallies.
The Constitutional Court oversees cases of violations of Thailand's charter, which was rewritten after the removal of Yingluck's brother, billionaire former premier Thaksin Shinawatra, by an army coup in 2006.
Critics accuse it of driving through Yingluck's case and allege previous rulings show that it is politically biased against the Shinawatras.
In 2008, the court forced two Thaksin-linked prime ministers from office.
It also annulled the February election called by Yingluck to shore up her flagging administration, citing widespread disruption by opposition protesters.
Yingluck has also been charged by anti-graft officials with neglect of duty in connection with a costly rice subsidy scheme that critics say fomented rampant corruption.
An unfavourable ruling by that body could also lead to her impeachment and a five-year ban from politics.
Thaksin lives overseas to avoid jail for corruption convictions.