Bangkok, Thailand – An aerobics class is under way as a sober-suited Prime Minister Prayuth Chan-ocha walks briskly into central Lumphini Park, accompanied by city officials and a pack of journalists.

The instructor gives up on her routine as the class of mostly older men and women peels away to greet the general who led the military coup against Thailand’s elected government in 2014, promising to bring peace and stability to a bitterly divided country.

Prayuth obliges them with photos and manages a smile and a wiggle as an elderly man urges him to join in.

“I’m here to work,” he tells Al Jazeera gruffly, explaining why he has opted to wear a suit rather than gym clothes and trainers.

Thailand’s long-delayed election is weighted in favour of the military and is taking place in a still-restrictive environment, but the keenly fought campaign has given a platform to politicians who have long been denied a voice under the military regime’s repressive rule, reawakening Thai hopes for democracy.

For Chris Baker, a historian and political analyst who has lived in Thailand for many years, a poll that was expected to be a walk in the park for Prayuth has suddenly become more exciting.

“We have no idea what might come out at the end of the week,” he said at a forum organised by Thailand’s Foreign Correspondents Club on Tuesday.

Prayuth hopes Sunday’s election will be the moment he transforms himself from a military ruler into a civilian leader, on the back of a constitution and electoral system that makes it difficult for Thailand’s major political parties to win a large majority and form a government and ensures the military’s continued influence.

Under new legislation, all future governments are expected to follow a 20-year national development plan that critics say locks Thailand into an anti-democratic future.

‘Protect the country’ 

Prayuth, who turns 65 on Thursday, was born in 1954 in the northeastern province of Nakhon Ratchasima. He attended a military school before transferring to the Chulachomklao Royal Military Academy from where he joined the infantry.

“I told myself that I had to dedicate my life for him [God], home and the monarchy,” he said in a comment on his official website.

By 2008, Prayuth was the Royal Thai Army’s chief of staff and two years later became commander-in-chief. The coup, he said, was necessary to “protect the country from violence, uprising and bloodshed”.

Together, the military and the monarchy constitute the most formidable force in Thai politics, according to Prajak Kongkirati, an expert in Thai politics at Thammasat University in Bangkok.

Since wresting control of the country, Prayuth has developed a reputation for being prickly and irascible, with little time for the media. Last year, he brought a life-size cardboard cut-out of himself to a press conference and walked away, telling journalists to address their questions to the figure.

But in recent weeks, he has undergone something of a makeover, with his team sharing patriotic videos of smiling Thais – lyrics by Prayuth – and soft-focus portraits on social media. Prayuth, who has eschewed the campaign’s political debates, has also been photographed at carefully choreographed events such as the outing to Lumphini Park.

“In the past five years he has ruled with absolute power,” Prajak told Al Jazeera. “But elections are about winning the hearts and minds of voters. The army and traditional elites have never been skillful at doing that.”

Military-dominated Senate

Under the new constitution that may not matter. The political system it has created makes it possible for Prayuth to become prime minister without Palang Prachartat, the party that has nominated him as their only candidate for the position, even winning a majority.

Instead, it is possible for Palang Pracharat to form a government with only 126 seats and the support of the upper house, a 250-seat body appointed entirely by the military where six seats are reserved for senior members of the junta.

“Under this constitution, it will be possible for Prayuth to come into power as a minority government, which will automatically make the majority in the house of representatives [the lower house] the opposition,” said David Streckfuss, an expert on Thailand based in Khon Kaen in Thailand’s northeast.

“No parliament can work this way. It’s a recipe for a government that won’t be able to govern.”

While most analysts expect Prayuth will still manage to become prime minister, the electoral dynamics – the complicated system, the high turnout in early voting last Sunday, and the impact of some seven million new voters – mean the outcome is no longer the foregone conclusion that many thought it would be.

Pheu Thai, which is expected to win most seats in the lower house, and newcomer Future Forward are both opposed to the military in politics, while Democrat leader Abhisit Vejjajiva, a long-time opponent of Pheu Thai, has left the door open to working with Palang Pracharat, but not Prayuth. Palang Pracharat itself might find it has to make deals with other parties in order to get its 126 seats.

“When Prayuth is left out of the equation we are left with a party of elected MPs,” Abhisit told Al Jazeera in an interview. “Left to themselves these elected MPs can break away.”

The general himself has remained largely inscrutable.

He declined Al Jazeera’s request for an interview, but earlier this week gave an insight into his vision for the country while visiting a hospital in the south. Thailand, he said, was like a family and he was “the father”.

As Prayuth strides through Lumphini on his way to check out a cluster of food stalls, Tourism and Sports Minister Weerasak Kowsurat admits the general’s sense of humour can sometimes be misunderstood.

“He likes to tease,” Weerasak said, insisting the public image of the grumpy general was not entirely fair.

Having worked as a minister in the military government for 14 months, he said Prayuth had the ability to grasp complex issues and the skills to run the country.

“He can see things from lots of different angles,” Weerasak said.

‘We need soldiers’

Three women in yellow shirts with “Long Live the King!” written on the back stand on a bench and chant Prayuth’s name, as the general, who has now removed his jacket and rolled up his sleeves, marches onwards, security and journalists struggling to keep up.

Kiat, 64, works out in the park twice a week and made sure she was in Lumphini because she had heard Prayuth would be visiting.

She said she has no concerns about the army’s continued role in politics, because the armed forces intervention brought an end to the political protests that had paralysed the country.

“The previous governments always made things messy,” she said. “We need soldiers.” A friend chips in that he likes the military government’s plans for improving Thailand’s roads and railways.

But other city residents are more sceptical.

Sukanya Kongprasert, also 64, said she supports Pheu Thai because she thinks they can do more to help the economy.

“What has Prayuth done?” she asked as she wound up her morning walk. “He has done nothing.”

Half an hour after arriving, Prayuth’s black Mercedes is waiting to take him to his next appointment. His pace has not flagged.

But as a journalist shouts out to ask him what he plans to do if Sunday’s vote, against the odds, doesn’t go his way, Prayuth reveals a flicker of impatience.

“We don’t think about winning or losing,” he said gruffly. He scans the crowd, gets in his car and is gone.

Additional reporting by Haithairat Phaholtap