The ruling means she immediately loses her job, which she had held for about a year.
Paetongtarn was suspended from her duties on July 1 when the court agreed to hear the case against her, and Deputy Prime Minister Phumtham Wechayachai took over her responsibilities.
Paetongtarn’s leaked June 15 call with Hun Sen was aimed at easing tensions over competing claims to territory along their border, but sparked outrage in Thailand because Paetongtarn seemed overly friendly in discussing a matter of national security and appeared to malign a Thai army general.
Audio of the call was leaked online by Hun Sen, who was Cambodia’s prime minister for 38 years until his son Hun Manet took over the job in 2023.
The phone call came as long-standing tensions over the border heightened after a Cambodian soldier was killed in a brief incident of violence in disputed territory in May.
In late June, the two countries engaged in five days of combat that killed dozens of people and displaced more than 260,000.
The court’s ruling puts the ruling coalition led by Paetongtarn’s Pheu Thai party on shaky ground.
Controversy over the phone call caused the Bhumjaithai Party, the biggest partner of Pheu Thai, to drop out, leaving the coalition with a slim majority of seats in the House of Representatives.
It is also a blow to the political machine of Paetongtarn’s father, former Prime Minister Thaksin Shinawatra, who was ousted from power by a 2006 military coup but has managed to remain a dominant force in Thai politics, chiefly by supporting proxy parties such as Pheu Thai.
His political strength comes from the populist policies he espoused and the vast fortune he earned in the telecommunications sector.
