The opposition on Wednesday demanded Prime Minister Prayut Chan-o-cha resign over his failure to recite the complete oath of office, an omission that speakers during the general debate said invalidated the cabinet's legitimacy.
Opposition and Pheu Thai Party leader Sompong Amornwiwat told the parliament that the constitution required the complete oath be taken, and Gen Prayut's failure to do this meant the cabinet was in violation of the constitution.
When Gen Prayut led the cabinet's oath-taking ceremony on July 16, he failed to recite the last sentence of the oath required by the constitution.
Section 161 of the 2017 constitution prescribes: "Before assuming duties, cabinet ministers must swear an oath to His Majesty the King as follows:
"I (name of minister) swear I will be loyal to His Majesty and perform my duties honestly for the benefit of the country and the people. I will also uphold and comply with the constitution of the kingdom in every aspect."
Mr Sompong said the prime minister had led several swearing-in ceremonies, but on July 16 he did not use the document that the prime minister's secretariat prepared for him. The opposition leader asked if the prime minister had intended to avoid saying the full oath.
He said the incomplete oath had a negative impact on the legitimacy of the cabinet and its decisions.
Anudith Nakornthap (Pheu Thai) said the incomplete oath invalidated the status of the cabinet as the cabinet had failed to promise that it would abide by the constitution.
He demanded Gen Prayut take responsibility by resigning from the position of prime minister.
Piyabut Saengkanokkul (Future Forward) said Gen Prayut set a precedent, that subsequent cabinets could have the liberty of taking an oath of their own content.
Seri Ruam Thai Party leader Pol Gen Sereepisuth Temeeyaves said the prime minister did not adhere to the constitution and the incomplete oath deprived him of the legitimacy to announce government policies in the parliament, and of the right to national administration.
He also accused the prime minister of reading from a false document while reciting the oath.
Pol Gen Sereepisuth also called on Gen Prayut to resign.
Cholanan Srikaew (Pheu Thai) accused Gen Prayut of intending to maintain his power as chief of the National Council for Peace and Order, saying the incomplete oath prevented the new government from legitimately taking office and replacing the NCPO.
He suggested Gen Prayut resign or replace cabinet ministers, so there could be a fresh and rightful cabinet swearing-in.