
"The speech was aimed at forestalling criminal punishment. It was a hasty attempt to seek a royal pardon when the case [against Thaksin] was not yet completed," Dej-udom said.
He said Thaksin's speech was also intended to reduce the credibility of the judiciary and could be regarded as contempt of court.
"In my experience, I have rarely heard any convicted person publicly say he was 'forced to get jail', not even those sentenced to death," he said.
Dej-udom warned that those supporting Thaksin giving such a speech or having it broadcast could be regarded as accomplices. Political office holders could risk impeachment for a severe violation of the code of ethics.
The Supreme Court's Criminal Division for Political Office Holders last month sentenced Thaksin to two years in prison in connection with the Ratchadaphisek land case. His wife, Pojaman, who had bought a coveted plot of land from a state agency at an unusually low price, was acquitted in the same corruption case, because she was not a public official.
Special Branch police earlier this week concluded that Thaksin's speech contained no message that could be regarded as lese majeste, a criminal offence that carries a penalty of three to 15 years in prison.
Thaksin made his controversial speech during a gathering of more than 50,000 supporters in Bangkok's Rajamangala Stadium, organised by hosts of the "Truth Today" political talk show on the state-run NBT channel.