(Bloomberg) -- Thailand’s Move Forward, the party that won the most seats in the May general election, is trying to strip some of the Senate’s powers after the military-appointed upper house of parliament blocked pro-democracy leader Pita Limjaroenrat’s bid to become prime minister.

Move Forward submitted a bill Friday to abolish an article in the 2017 military-backed constitution, which gives the unelected Senate the power to select the prime minister alongside the elected lower house.

This isn’t the first time that someone is trying to challenge the Senate’s voting right. Six attempts have been made in vain since 2020 by political parties and civil society groups to curb the power of the Senate, because such a proposal ironically needs support from at least a third of the 250-member upper house to pass.

Move Forward’s submission came a day after its leader Pita, the sole nominee of the eight-party coalition that has staked a claim to form Thailand’s next government, was thwarted in his bid for premiership by senators, the majority of whom rejected Pita outright or abstained from voting. In doing so, they undermined the result of the May 14 election where voters had overwhelmingly supported pro-democracy parties. 

READ: Thai Conservatives Stop Pro-Democracy Candidate From Becoming PM

“We don’t know how many times the prime minister selection will be held until it concludes. So, we can do this hand in hand,” Chaithawat Tulathon, secretary-general of Move Forward Party, told reporters at the parliament house. “Since the Senate didn’t want to vote anyway, we’re only looking for a solution for everybody.” 

Among the 250-member Senate, as many as 159 members abstained from voting and 34 voted against Pita outright on Thursday. Only 13 backed the popular mandate. But Chaithawat said the party will seek support from more senators for Pita at the next round of prime minister selection next week.

Many members cited Move Forward’s platform to amend Thailand’s lese majeste law, which prohibits criticism of the king or other royals, as a reason for withholding support. Pita has vowed to not back down on the proposal, raising further tension with the pro-military royalist establishment. 

The bill was accepted by house speaker Wan Muhamad Noor Matha, who confirmed at the briefing that the second vote to select the prime minister will be held by the joint National Assembly on July 19, at 9:30 a.m. in Bangkok. 

“I’ll process this as soon as possible as this is an urgent matter,” Wan said.

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