The National Anti-Corruption Commission (NACC) insists Pheu Thai's rejection of the Constitution Court's charter amendment ruling does not affect its inquiry into impeachment and criminal cases against 312 MPs and senators.
Parliament President Somsak Kiatsuranon and Senate Speaker Nikhom Wairatpanich are among the legislators who face NACC investigation for their role in the draft charter amendment seeking to change the make-up of the Senate, which the court on Wednesday ruled was unlawful.
Five petitions have been filed to the NACC by various anti-government camps seeking to remove the 312 MPs and senators who supported the draft from office. The NACC has agreed to combine the petitions into a single case.
NACC member and spokesman Vicha Mahakhun said yesterday the commission will meet on Tuesday to set out a framework for the investigation.
The accused will be allowed to clarify the allegations against them before the panel, he said.
Mr Vicha played down the Pheu Thai Party's stance against the court ruling, saying their rejection has nothing to do with the NACC's work. He insisted all state agencies are bound by the ruling.
"The NACC cannot go the other way. It needs to base its investigation on the court ruling," Mr Vicha said.
As for the court judgement that some MPs voted improperly on the behalf of others, Mr Vicha said: "This case also falls under the NACC's investigation because it is an issue of ethical behaviour."
However, the NACC first needs to look into the details of this ruling. "Now we will focus on the legislator impeachment case," he said. "We have never been slow to impeach, whoever they are."
Mr Nikhom yesterday said he is not worried about the probe and he has already prepared evidence to fight the accusations. He said he will "let things be as they are meant to be throughout the process". The NACC's findings will be passed on to the Supreme Court's Criminal Division for Holders of Political Positions.
Mr Nikhom said the accused senators will meet on Monday to discuss whether they want to follow Pheu Thai's lead.
"We're in the same boat, so we should go in the same direction," he said.
Meanwhile, the pro-Pheu Thai United Front for Democracy against Dictatorship (UDD) yesterday petitioned the NACC to throw out the impeachment case.
UDD lawyer Kharom Phonppornklang claimed the NACC has no authority to consider the case because the legislators only did their duty and their actions had nothing to do with corruption.
UDD co-leader and Pheu Thai list-MP Chertchai Tantisirin said he, together with fellow Pheu Thai MPs, will on Monday file charges with the police against five Constitution Court judges for allegedly violating the Criminal Code.
Among the charges is an accusation of lese majeste because the judges ruled against the charter amendment draft after the prime minister had sent it to His Majesty the King for endorsement.