The new constitution is bound to have its critics but three key members of the National Reform Council (NRC) believe it will win endorsement for a number of reasons.
For a start, all NRC members would lose their jobs and more than one million baht a year in compensation if they say no.
The 2014 interim charter drafted by the military government states that the NRC will be dissolved if the draft constitution is turned down and new members will be appointed until a charter is endorsed.
The NRC on Monday will begin a week-long consideration of the 50,000-word document that contains 315 sections. Many parts are not seen as contentious but some, including a bewildering new electoral system, have prompted a lot of debate.
Wanchai Sornsiri, a spokesman for the NRC whips, said the prevailing speculation that his colleagues would reject the draft charter could be wrong.
Despite criticism, the new draft charter is better than the 1997 and 2007 constitutions, he said.
Nipit Intarasombat, a Democrat Party deputy leader, predicted earlier that the draft would be voted down by the NRC.
"The Constitution Drafting Committee (CDC) wrote it for 60 million people, not some 5,000 politicians," Mr Wanchai said. "We need to solve the country's problems and prevent corruption and malfeasance because politicians are so corrupt, causing enormous damage to the country.
"Therefore, it doesn't matter if politicians aren't happy with it. What's important is what the people and the country will benefit from it."
He is confident the new charter will definitely be endorsed.
"The CDC members came from us. We're on the same side. We've worked side by side all along so there's no reason to believe the draft would be rejected," he said.
"We've worked together for almost a year. What's the point of rejecting the charter so the National Council for Peace and Order (NCPO) and the government could stay on? Politicians should stop imagining things."
Responding to Mr Nipit's complaint that the CDC had never discussed its work with political parties, Mr Wanchai said: "We've always listened to the views of all groups including politicians. But it's up to us whether to believe them.
"We are the ones who make the decisions because we have the experience, the brains, the lessons and the information. We only choose what's best for the country.
"We invited politicians several times, including Democrat Party leader Abhisit Vejjajiva. We also have documents submitted by parties and we took all of them into consideration when drafting the charter."
Sombat Thamrongthanyawong, chairman of the NRC's political reform committee, said that despite criticism, he saw about a 70% chance that the NRC would endorse the draft as members believed it combined the strengths of the previous two charters but was better than they were.
However, there appears to be a certain wariness about asking Thai citizens what they think. A spokesman for the NCPO earlier this week said that a referendum could be divisive.
"If the draft is put to a national referendum, I think there will be a political element to it," said Mr Sombat. "If a party doesn't like the new election system, which it believes will weaken it, it will drum up support among voters and ask them to reject it.
"On the other hand, if the draft is rejected, an election will be delayed. So the parties will have to weigh the pros and cons carefully."
Prasarn Maruekapitak, an NRC whip, said the charter writers came from the NRC and 80-90% of the 246 suggestions made by the NRC were integrated in the draft.
"People's response is also important. If the writers can create a through public understanding until people approve it, the NRC will most likely endorse the draft," he said.
However, he acknowledged that some members might be swayed by the prospect that the existing NRC members would be out of a job if the charter fails to pass.
"As well, after the debate, if the CDC embraces the amendments proposed by the NRC and agrees to compromise, such as it did on how the PM comes to office, the NRC will likely accept it," he said.
"I think there are more NRC members who like the draft that those who don't."
Mr Prasarn blamed the media for sensationalising stories about the opposing views of the few NRC members who do not agree with the draft charter. "They tend to ask people like Mr Nipit, Mr Abhisit or Chaturon Chaisang [a Pheu Thai deputy leader].
"These people will lose their power so they don't agree with it. Nobody asks the views of small parties which will benefit from the MMP (mixed member proportional) system," he added.
"If I were to guess, the Pheu Thai party would reject it, the Democrats would be uncertain while small parties would embrace it."
Section 306 of the draft prescribes that after the charter is promulgated, the existing NRC will remain in office until the new Senate is ready, a process likely to take around 7-8 months.
According to a royal decree on the NRC's salary and compensation, the chairman receives a position allowance of 74,420 baht a month and an extra payment of 45,500 baht, totalling 119,920 baht a month. The deputy gets 73,420 baht and 42,500 baht (115,920 baht total) while members gets 71,230 baht and 42,330 baht (113,560 baht total).
CDC members do not receive monthly salaries but are entitled to meeting allowances of 6,000 baht for each meeting. The chairman gets an additional 3,000 baht for each meeting.
The CDC members who do not have positions in the NCPO, the National Legislative Assembly or the NRC get 50% more compensation.
Members of the committees of the NLA and NRC receive a meeting allowance of 1,500 baht per meeting while subcommittee members get 800 baht.
