Suthep Thaugsuban, the former Democrat Party fixer whose street protests paved the way for the 2014 coup, on Friday announced his wholehearted support for the draft constitution that will be put to a public referendum on Aug 7.
Mr Suthep made his case in a Facebook Live video and said he would make more appearances online to discuss why people should support the charter drafted by a military-appointed committee.
The online campaigning appears to occupy a grey area legally as the referendum law forbids public displays that attempt to influence opinion one way or the other. The only acceptable messages are those that encourage citizens to go out to vote.
Earlier this month 17 Pheu Thai Party politicians posted strongly worded anti-charter messages on Facebook, but the military government dodged the question of whether they would be prosecuted, saying it would be up to the Election Commission to decide.
Mr Suthep, to no one's surprise, made it clear where he stood.
"I have firmly decided that I will certainly cast my vote in the referendum and I will vote to accept this constitution," he said. "Anyone who reads the constitution will share my thoughts. For those who have limited time, just reading the preface will give them an understanding."
His first Facebook Live broadcast was aired at 2pm on Friday, the 84th anniversary of Thailand's transition from absolute monarchy to democracy.
The new constitution was drafted because the country had suffered unstable politics as a result of some groups of people who had abused power, failed to take responsibility for the nation and the public and rejected rules, said Mr Suthep.
The draft charter, he said, would lead to national reform focused on law enforcement, public education and the promotion of morality among the citizenry.
Elections alone were not enough to guarantee true democracy because they tended to feature vote-buying, electoral fraud, threats against eligible voters and the abuse of government offices, Mr Suthep said in his nine-minute broadcast.
Importantly, the draft charter includes a mechanism that would allow the country to pass through a crisis, said the veteran Democrat Party strongman who served several years in parliament, most recently as deputy premier in the administration of Abhisit Vejjajiva from 2008-11.
Mr Suthep recalled how he tried in vain to call for a new prime minister to break the political deadlock in 2013 and 2014, before he took his People's Democratic Reform Committee (PDRC) campaign onto the streets of Bangkok to demand the ouster of the Pheu Thai government led by Yingluck Shinawatra. The result was paralysis of government before the army led by Gen Prayut Chan-o-cha took power on May 22, 2014.
Mr Suthep now heads the Muan Maha Prachachon for Reforms Foundation, which has the stated aim of educating people about the political process and encouraging their participation. He has insisted that he will have nothing more to do with party politics.
He said he was also impressed with the provisions in the draft charter designed to block corrupt people from obtaining political power and for promoting government-people partnerships.
He said the content of the draft charter matched what the PDRC had campaigned for, adding that he would gradually explain why people should vote for the draft charter daily at 2pm.