Move Forward Party leader Pita Limjaroenrat said at a news conference on Thursday that the proposed coalition would have 313 seats in the House of Representatives, a solid majority of its 500 members.

“The key message of today’s news conference is to assure the public that my coalition is firmly taking shape,” said Pita, a Harvard-educated businessman. “There’s momentum, there’s progress and we also have a very clear road map from today until the day I become prime minister.”

Despite the overwhelming support, fears exist among the coalition’s supporters that Pita’s military-aligned opponents may use the unelected Senate to block him from office.

Under Thailand’s constitution drafted under military rule after a 2014 coup, the lower house and the 250-seat Senate must vote together to select a new prime minister. All of the senators have been appointed by the generals who took power after the coup.

Because of the joint vote, Sunday’s election victor is not certain to take power.

The alliance on Thursday added two more members and three seats, but it still appears short of the 376 votes needed from the 750-member bicameral legislature to vote in a prime minister to form a government.

Young voters were particularly attracted by Move Forward’s policies, including a proposed amendment of Thailand’s harsh lese-majeste law, under which criticising the monarchy is punishable by up to 15 years in prison.

About 200 people have been charged in the past few years, many from a youth-led protest movement.

Critics said the law is frequently misused to punish critics of the government. Conservatives who consider the royal institution sacrosanct strongly oppose any amendment.

Pita, 42, was dealt a blow on Wednesday when the third-place finisher, the Bhumjaithai Party – a potential game-changer with its 70 seats – said it could not back any prime minister who supports amending or abolishing a law against insulting the powerful monarchy.

Asked about Bhumjaithai’s declaration, Pita said: “That is their matter. The eight parties have a position and clarity.”

Coup-weary public

Pita said his plans to take office include teams to work out any differences among the parties and “make sure there is a continuation of power, minimising risk as well as reducing destabilising factors that could damage the country or the economy or the financial markets”.

Move Forward’s progressive agenda resonated with a public weary of nine years of military-steered rule under Prime Minister Prayuth Chan-ocha, who led the 2014 coup as army chief.

The party enjoyed a surge in support before Sunday’s polls, driving it to become the largest party in the legislature with 151 seats. Prayuth’s United Thai Nation Party captured only 23 House seats.

Move Forward edged out another opposition party, Pheu Thai, aligned with popular former Prime Minister Thaksin Shinawatra, who was ousted in a 2006 coup.

Pheu Thai leader Cholanan Srikaew pledged unequivocal support for Pita as prime minister and for Move Forward’s bid to form a new government.

All senators voted for Prayuth as prime minister after the 2019 elections, allowing him to remain in office despite a Pheu Thai victory in those polls. Some senators have already said they will not support Pita as prime minister because they oppose any change to the lese-majeste law, known as Article 112.

“I confirm we want to protect the monarchy but also not allow 112 to be used to harm other people,” said Sudarat Keyuraphan, leader of the Thai Sang Thai Party, which is part of Pita’s coalition.

She said each party in the coalition has a different stance on the law. “We have to talk about this article as well as all the other policies,” she said.

Pita said the parties will sign a memorandum of understanding next week to create a common understanding of how they will work together as a government.

He also brushed off a pending case filed with the election commission seeking to disqualify him over shares he allegedly holds in a media company.

“I’m not worried. … I understand there are many dimensions in politics,” Pita said. “As a public figure I can accept the investigation.”