The Bangkok South Criminal Court on Tuesday acquitted veteran Democrat Chuan Leekpai of defaming former prime minister Thaksin Shinawatra when criticising Thaksin's southern security policy in 2012.
The case concerned Mr Chuan's remarks made at the Decmorat Party's political school in Bangkok on Oct 28, 2012. He was critical of the way Thaksin handled security issues in the far South.
Mr Chuan, a former prime minister and former parliament president, referred to a security operations policy then-prime minister Thaksin set out for security authorities on April 8, 2001.
The policy was in response to a bomb explosion at Hat Yai train station in Songkhla province on April 7, 2001, when one person was killed and 38 others injured.
Mr Chuan said the policy was a mistake and was followed by more violent incidents in the far South, including the robbery of more than 400 guns from the 4th Development Battalion in Cho Airong district of Narathiwat province on Jan 4, 2004. He also said about 5,700 people had been killed in the violence in the southern border provinces.
Mr Chuan said on Tuesday that the court ruled that he had the right to criticise Thaksin's policy.