Senators have threatened legal action against opposition leader Natthaphong Ruengpanyawut unless he apologises within three days for remarks alleging the Senate is part of a "blue regime" rooted in the 2017 Constitution, which he described as a legacy of a coup.
A group of 89 senators, led by Senate whip spokesperson Phisit Apivatanapong, issued the warning at a press conference at parliament on Monday, rejecting accusations made in Mr Natthaphong's Facebook post on Friday, in which he described the current Senate as a "blue Senate" created under the 2017 Constitution.
Mr Phisit called the allegations false and "the worst kind of conduct", insisting senators operate independently and are not under the control of any political party or institution.
He said legal action would be pursued if Mr Natthaphong failed to apologise within the deadline.
Rejecting claims that the Senate is a product of coup politics, Mr Phisit said the 2017 Constitution had been approved by referendum and followed by general elections in 2019, 2023 and 2026, all of which included parties linked to Mr Natthaphong, from the Future Forward Party to the Move Forward Party and now the People's Party (PP).
He also defended the Senate's selection process, saying senators were chosen through an intra-professional mechanism and should be regarded as legitimate unless ruled otherwise by competent authorities or the courts. Senators, he said, have acted impartially and in accordance with the constitution and law.
Asked whether the dispute would affect Senate consideration of the PP's constitutional amendment proposal, Mr Phisit said it would not influence voting.
However, he questioned whether the party was sincere about reform, noting that Section 256 requires support from one-third of senators.
PP leader Natthaphong did not commit to an apology, saying his remarks referred to a broader political structure rather than individuals. He said his party would support any constitutional draft aligned with its principles, including a people-linked charter and no expanded Senate privileges.
In another development, Prime Minister's Office Minister Paradorn Prissananantakul said the timeline for rewriting the constitution remains unclear, as additional draft proposals may still be submitted.
He added that the Bhumjaithai-sponsored bill is not final and that its submission reflects the party's commitment to charter reform.
In Thai politics, the colour blue predominantly symbolises institutional conservatism and the rising political influence of the ruling Bhumjaithai Party. Unlike western politics where blue often denotes liberalism, blue in Thailand represents the traditional establishment and right-wing nationalism.
