Introduction

On 21 May 2019, the Indonesian General Elections Commission announced the long-awaited electoral results: the incumbent President Joko Widodo (Jokowi) and his running mate, the Islamic scholar Ma’ruf Amin, had won, garnering 55.50 per cent of the total votes, against former general Prabowo Subianto and his vice-presidential candidate, Sandiaga Uno, who obtained 44.50 per cent. The incumbent was backed by a coalition of nationalist and Islamic parties led by the Partai Demokrasi Indonesia Perjuangan (Indonesian Democratic Party of Struggle or PDI-P, for short) whereas Prabowo was endorsed by his own party, Gerindra, and the Islamist-oriented Partai Keadilan Sejahtera (Prosperous Justice Party or PKS, for short). This was the second presidential contest for Jokowi and Prabowo as they were also contenders in the 2014 election.

The election campaign was also one of the most divisive in Indonesia's electoral history. Most notably, it showcased the culmination of Indonesia's religious–pluralist binary electoral politics, with Prabowo's camp relying on the mobilization of Islamist sentiments and Jokowi's camp generally seen as championing pluralism despite having a vice-presidential candidate who is considered by many as religiously conservative. The key term here is electoral politics as religious polarization is aggravated mainly during elections.

Despite the comfortable margin of 11 per cent that he had achieved, Jokowi won in fewer provinces than he did in 2014. Notably, he lost in six of the ten provinces in Sumatra, which, with its 37.8 million voters, is the island with the second largest number of voters after Java. Like the rest of the Indonesian archipelago, Sumatra is predominantly Muslim (87 per cent), while Christians make up 10.7 per cent of the population, and Buddhists (1.4 per cent), Hindus (0.4 per cent) and Confucians (0.1 per cent) are present in smaller numbers. Yet, the island is ethnically heterogeneous, with Javanese (30.2 per cent), Batak (14.4 per cent), Malay (13.2 per cent) and Minang (11.4 per cent) forming the main ethnicities, while smaller groups include the Chinese (1.5 per cent).

Of Indonesia's thirty-four provinces, none has more strongly shown religious binarism than North Sumatra, one of the most religiously and ethnically heterogeneous provinces in the archipelago. Here, Jokowi won by a negligible margin of 4 per cent.