A persistent whistleblower was behind the September 9 verdict that saw former prime minister Thaksin Shinawatra finally jailed on convictions he had managed to avoid for over a decade.
Chanchai Issarasenarak, a four-time former Democrat MP, has devoted the past three decades of his life to fighting for transparency and accountability among Thai politicians and bureaucrats.
He has filed numerous petitions alleging corruption in public life, winning some high-profile cases but losing others.
His crusade has landed him in hot water, with powerful business interests suing him for defamation, though he has always managed to escape conviction.
His latest target, Thaksin, was sent to prison for one year in early September after the Supreme Court's Criminal Division for Holders of Political Positions ruled that his 2023 detention in hospital could not be counted as time served behind bars.
The court found that his health issues were not severe enough to require hospitalisation and that he and his doctors had intentionally prolonged his medical stay with unnecessary minor surgeries.
Thaksin originally faced eight years in prison after being convicted in three corruption cases stemming from his tenure as prime minister between 2001 and 2006, when he was ousted in a military coup.
However, after he returned to Thailand in 2023, his term was cut to one year by a royal pardon.
3 petitions in 14 months
The historic September 9 ruling marks Chanchai’s biggest success in a decades-long campaign against corruption.
But it also proved to be the 72-year-old whistleblower’s toughest fight so far.
Chanchai filed three petitions over 14 months before the top court finally agreed to investigate his claim that the Corrections Department failed to enforce Thaksin’s prison sentence, allowing him to stay six months in a luxury suite at the Police General Hospital before being released on parole due to age.
The whistleblower appeared to be fighting a hopeless battle after his first two petitions were dismissed, only for his stubbornness to pay off on his third attempt.
Recently, Chanchai said that he felt obliged to take on the Thaksin case out of a duty to uphold social justice and “genuine rule of law”.
“The justice system’s credibility must not be destroyed for any single individual,” he said.
Describing the verdict as “historic and unprecedented for Thailand”, the whistleblower said it would serve as a warning for politicians and other people in power.
“Those who are corrupt or abuse their power must now be mindful that even someone as powerful as Thaksin was not spared by the court,” Chanchai said.
Defending the rule of law
His latest crusade to defend the rule of law began in late 2023 amid mounting public discontent over Thaksin’s long hospital stay.
On the day of his return to Thailand, the ex-premier was transferred from Bangkok Remand Prison to a premium ward on the 14th floor of a Police General Hospital building.
Chanchai agreed with many observers who saw no sign that Thaksin was suffering serious illness when he landed in Bangkok aboard his private jet on August 22, 2023, ending 15 years of self-imposed exile overseas.
After noting what he called “VIP treatment” for Thaksin on his return, Chanchai began studying laws and regulations on the transfer of ill prisoners for treatment.
Normal procedure dictates that seriously ill inmates are treated at the well-equipped 350-bed Corrections Department Hospital, located near Bangkok Remand Prison.
Patients are only transferred to another medical facility when this hospital cannot provide adequate treatment.
Chanchai said his suspicions were aroused in November 2023, more than two months after Thaksin was admitted to the Police General Hospital – an unusually long time for in-patient treatment.
Remembering Thaksin’s earlier boast that he would return to Thailand without serving prison time, he decided to act.
Relentless determination
On December 19, 2023, Chanchai filed a complaint with the Supreme Court, alleging that Thaksin’s hospital stay did not constitute imprisonment and that certain Corrections Department officials may have helped him avoid jail time.
However, the court dismissed the petition, ruling that although it had issued the verdict, it had no authority to force the Corrections Department to carry it out.
On February 15, 2024, just three days before Thaksin was due for parole release, Chanchai filed his second petition with the court, arguing that the ministerial decree cited by the Corrections Department to justify Thaksin’s release from the hospital contradicted existing laws.
The court upheld its original ruling, stating that enforcing Thaksin’s sentence and allowing him to be treated outside prison fell under the Corrections Department’s jurisdiction.
The court had no power to rule whether the department’s handling of Thaksin’s sentence was in line with the law, it added.
Chanchai, however, refused to give up. He spent the next six months gathering more evidence, including a 1939 Supreme Court ruling in a similar case.
He submitted his third petition on January 10, 2025, citing legal precedent that gave the court power to investigate whether Thaksin was serving the sentence it handed down.
The lawsuit also warned that failure to probe this matter could constitute a violation of the law.
On April 30, the Supreme Court dismissed Chanchai’s third petition – but this time ordered an inquiry into whether its prison sentence against Thaksin had been properly implemented.
After over four months of hearings, the inquiry concluded with the verdict delivered on September 9.
Businessman turned politician
Chanchai was born on August 10, 1953, in Nakhon Nayok province, just north of Bangkok.
He earned bachelor's and master’s degrees in political science from Ramkhamhaeng University.
He began his career in business before switching to politics in 1995 when he was elected to Parliament as a Democrat Party MP representing his home province. He was re-elected three times under the Democrat banner.
However, his success at the ballot box came to an end in 2011, when he failed to win back his seat, before again falling short at the 2019 election as a Democrat list candidate.
After the 2014 military coup, Chanchai was appointed to the National Reform Steering Assembly, serving as vice chairman of its subcommittee tasked with studying and recommending measures to combat corruption.
