M A’RUF AMIN cuts a demure figure. Short and smiling, he dresses in sandals, sarong and skullcap. The 75-year-old Muslim cleric is likely to be Indonesia’s next vice-president. He and his running-mate, Joko Widodo, Indonesia’s president, who is usually known as Jokowi, have a 20-percentage-point lead in the polls ahead of the election in April. He says governing with Jokowi will be like “a game of badminton doubles”. When the president goes toward the net, Mr Amin should drop back. When one steps left, the other moves right.

Mr Amin certainly provides his partner with a type of balance. Religion looms large in Indonesian elections. Many in the world’s third-largest democracy see Jokowi as not devout enough, a serious charge in an overwhelmingly Muslim country. When he was first elected, in 2014, rumours circulated that he was in fact a closet Christian. Most religiously inclined parties supported his opponent in that election, Prabowo Subianto. Mr Amin is the head of Nahdlatul Ulama ( NU ), a Muslim organisation that claims 50m members, as well as the chairman of the country’s main clerical council. By adding Mr Amin to his ticket in place of his current, term-limited vice-president, Jokowi doubtless hopes to attract more pious voters in his re-match against Mr Prabowo next year.

But some worry that Mr Amin is less of a counterbalance and more of an albatross. NU is a moderate organisation, which aims to defend the syncretistic, folksy form of Islam that was once the norm in Indonesia against the more austere (some would say purer) version that has become commonplace in cities. But Mr Amin himself has at times espoused doctrinaire views. He has issued fatwas against sects he deems deviant. He advocates a ban on gay sex, arguing that most Indonesians would approve. He would like to implement sharia, though only through the proper legislative process. In 2017 Mr Amin’s testimony as an Islamic scholar helped secure the conviction of Basuki Tjahaja Purnama (“Ahok”), a former governor of Jakarta and an ally of Jokowi, on trumped-up blasphemy charges. Mr Amin argues that the biggest problem facing Indonesia is a crisis of belief, rather than more common complaints such as corruption or bad roads.

At one level, the choice of Mr Amin seems to be helping Jokowi. Polls suggest that the most pious voters (those who pray at least twice a day and read the Koran) will plump for the president—the reverse of 2014, when a majority of them are thought to have opted for Mr Prabowo. Voters trust Mr Amin on religious matters more than they do his counterpart on Mr Prabowo’s ticket, Sandiaga Uno, a businessman and former deputy governor of Jakarta. But surveys also show that, among voters who are familiar with all the candidates, the vice-presidential choices reduce Jokowi’s lead over Mr Prabowo by six percentage points. The number of voters Mr Amin attracts to the ticket, in other words, may be outweighed by those he puts off.

Two compensating factors may have drawn Jokowi to Mr Amin. First, his age. Running for vice-president boosts a candidate’s chance of being elected to the top job in the future. Jokowi’s choice had to be approved by the leaders of the coalition of parties from which he derives his support in parliament. Most of them have a candidate they would like to see win the presidency at the following election, in 2024. The already elderly cleric is unlikely to be in the running then.

Second, Mr Amin is politically shrewd and ideologically elastic. Despite coming from humble stock, he has climbed to the upper echelons of political and religious life. He has positioned himself as an authority on the sharia economy and won lucrative positions on the compliance boards of big banks. Already, Mr Amin’s tone appears to be moderating. He says that Islamic schools should champion tolerance to curb the spread of violent radicals. He has been buttering up religious minorities and supporters of Ahok.

This apparent lack of fixed beliefs makes Mr Amin dangerous, some say. But just how dangerous depends on how big a role he is given. A convincing win would allow Jokowi to sideline Mr Amin. A narrow victory, in contrast, might leave him dependent on the religious camp that Mr Amin helps to cultivate. In the game of presidential badminton there is still much to play for.