Former senators facing impeachment proceedings rejected allegations Wednesday that they abused their authority and falsified a draft bill while testifying in their first hearing before the National Legislative Assembly (NLA).
Among the 38 former senators allegedly involved in a 2013 charter amendment to make the Senate fully elected, 29 attended the hearing to defend themselves before the NLA.
The National Anti-Corruption Commission (NACC) petitioned the NLA to impeach the former senators in connection with their support of the charter amendment, which was later ruled unconstitutional by the Constitutional Court.
In his opening statement, NACC commissioner Vichai Vivitsevi said the anti-graft agency divided the accused into four groups, based on varying degrees of support for the amendment.
The first group supported the amendment only in its first reading, the second group supported the first and second readings, the third group supported the first and third readings, and the last group supported all three readings.
Mr Vichai further accused the senators of amending the draft between parliamentary sessions, distorting it from the version previously presented before parliament.
He said their conduct was a severe breach of discipline.
"It is impossible that they had no knowledge of the draft bill being altered in between readings at parliament," he said.
While the former charter is no longer valid, the NACC still has legal authority to seek impeachment for the ex-senators, Mr Vichai insisted, citing the 1999 Organic Law on Counter-Corruption — which is still in effect — orders from the National Council for Peace and Order, and the current interim charter.
Former Kamphaeng Phet senator Krit Arthitkaew, a representative of the 38 defendants, rejected all of Mr Vichai's claims, saying the NACC's accusations and legal grounds for impeachment were incorrect.
In addition, a petition filed by Democrat Party figures with the NACC was invalid because it only included petitioners' signatures but not their addresses, nullifying it by law.
Former senator Withaya Inaya, another representative, maintained there was only one draft of the charter amendment bill, and it was not altered between readings. There have been last-minute changes to the draft, he said, but these were made prior to the inclusion of the bill in the senators' meeting agenda.
Mr Krit also pointed out irregularities committed by the NACC commissioners themselves. Commissioner Phakdee Photisiri failed to resign from his post at a private sector company within the allowed time frame following his appointment to the NACC, he claimed.
On Tuesday, an NACC sub-panel ruled to indict 250 former MPs on similar charges, and five ex-legislators also face criminal charges for swiping identification cards to register votes for absent colleagues when parliament was in session.
The five former MPs denied the charges.
Former Bangkok Pheu Thai MP, Polphum Wipatphumiprathetl, argued Wednesday it is one of the roles of lawmakers to amend the charter, according to the 2007 charter's Section 291. And Pheu Thai MP Yuthapong Charatsathien said he only switched voting machines because another legislator stole his seat.