The Constitutional Court said it will rule Wednesday whether to remove Prime Minister Yingluck Shinawatra from office on abuse of power charges in the Thawil Pliensri transfer case.
The premier appeared at the court Tuesday to deny the allegation, filed by anti-government senators who said the 2011 transfer of Mr Thawil from the post of head of the National Security Council was strictly for the benefit of the Pheu Thai Party.
After Ms Yingluck and Mr Thawil testified Tuesday morning Court's president Charoon Intachan said the nine-member bench had heard enough, and was ready to rule.
"The hearing is over... the court has decided to rule on May 7 at noon," he said.
The anti-government People's Democratic Reform Committee (PDRC) kept quiet and calm as well, as they hoped for an anti-Yingluck verdict. Red shirts plan began a rally Tuesday that couls spread if the court rules against her.
At the Constitutional Court, Ms Yingluck was adamant.
"I didn't violate any laws, and I didn't receive any benefit from the appointment," a composed prime minister told the judges.
But it is up to the court to decide that. If it votes that she abused her power, she will have to resign immediately.
The court could also extend its verdict to cabinet members who endorsed the decision to remove Mr Thawil. That is what anti-government forces hope, since it would remove an entire layer of Pheu Thai decision makers with ties to fugitive ex-premier Thaksin Shinawatra, always the top target of the protesters.
Prime Minister Yingluck Shinawatra was calm as she testified and answered questions at the Constitutional Court, but appeared obviously worried.
Pro-government "red shirts" have vowed to defend Ms Yingluck. Protests are certain and violence is possible if the court decision results in her removal Wednesday.
At least 25 people have died in political violence since Mr Suthep kicked off his PDRC campaign last November.
If Ms Yingluck is dismissed, a deputy prime minister can replace her as caretaker prime minister. But a decision to sack the cabinet would send politics into uncharted territory.
"Thailand will enter a legal limbo," according to Paul Chambers, director of research at the Institute of Southeast Asian Affairs at Chiang Mai University.
"There will be no cabinet, prime minister and no lower house. Only the senate," split between pro- and anti-Yingluck members much like the country itself.
Some believe the senate could seize the power to select a new government. The constitution is unclear on this point.
Critics accused the Constitutional Court again on Tuesday for rushing through Ms Yingluck's malfeasance case.
In 2008, the court forced two Thaksin-linked prime ministers from office. It also annulled the Feb 2 election, citing widespread disruption by opposition protesters.
The chairman of the United Front for Democracy against Dictatorship and red shirts on Tuesday accused the court of being bent on "overthrowing democracy".
"We red shirts will not allow any undemocratic change," Jatuporn Prompan added.
If Ms Yingluck survives Wednesday, she faces a second, immediate confrontation with the National Anti-Corruption Commission (NACC), which may charge her with with neglect of duty and failing to root out corruption in the rice-purchase scheme.
Those charges, too, would force her from office to face an impeachment vote in the senate.