Malaysia is just a few months or even weeks away from its most contentious election in decades. Mahathir Mohamad—Malaysia’s longest-serving prime minister, whose rule ended in 2003—is, at 92, working with opposition figures he once repressed to prevent his former protégé, the controversial Prime Minister Najib Razak, from securing another term. But breaking the 61-year winning streak of Mahathir’s former party, the United Malays National Organization (UMNO), will not be easy.

In fact, the pundits are still betting on Najib, with one pollster predicting that the incumbent could regain a two-thirds parliamentary majority, enabling him to amend the constitution. Mahathir has just a few months to change the political dynamic, by leading the opposition coalition, Pakatan Harapan (PH), and replacing the Pan-Malaysia Islamic Party (PAS) with his new party, the Malaysia United Indigenous Party (PPBM), as the primary alternative to UMNO.

While the PAS has only about 15% electoral support, it has managed to push the UMNO to implement elements of its nationalist-religious agenda. A strong enough showing by PH in the next election, however, would expose the PAS as politically dispensable, potentially freeing Malaysia from a toxic game of Islamist one-upmanship.

The impact of that game should not be underestimated. In recent years, religious intolerance has been on the rise in once-secular Malaysia. For example, the Arabic word for God, Allah, widely used by Arab and Indonesian Christians, is now reserved for Muslim use only. More alarming, the Home Ministry has banned a wide range of books, from the Indonesian translation of Charles Darwin’s On the origin of species to the writings of the Islam-friendly Western scholars John Esposito and Karen Armstrong.

The rise of a strict and exclusivist Islam in Malaysia reflects international trends and domestic dynamics. Ethnic-majority Malays—who were marginalised during colonial times, but now enjoy constitutionally guaranteed preferential treatment in the economy and education—must, by definition, be Muslim. The persistence of their favoured status hinges on the UMNO’s political dominance, or so UMNO claims.

While early UMNO leaders were anti-clerical, the party’s success in eliminating its leftist and liberal rivals left PAS as the face of the Malay opposition. When the modernist Mahathir came to power in 1981, Islamism became the PAS’s most effective ideological weapon against the UMNO.

And, indeed, the PAS leader, Hadi Awang, then a young and charismatic cleric, advocated a radical stance, labelling any Muslim who supported the UMNO an ‘infidel’, because the UMNO government had supposedly ‘perpetuated the colonial constitution, infidel laws, and pre-Islamic rules’. Hadi’s message helped to create a deep divide between the two ‘kinds’ of Muslims, to the extent that villages would have two mosques, two cemeteries and two clerics to lead prayers and officiate at ceremonies.

But where Hadi did the most damage was in undermining the legitimacy of Malaysia’s post-colonial state and social structures. When Malaysia was under British rule, it faced mass immigration of ethnic Chinese and Indians, and the emergence of a Christian native minority on the island of Borneo.

From a Muslim nationalist’s perspective, pluralism—together with secularism and democracy—were colonial impositions. Full decolonisation would demand restoration of the dominance of Islam and Muslims. According to this narrative, the Ottoman Empire offers a model of segregated, unequal, but peaceful co-existence of multiple ethno-religious communities. Minorities lived autonomously in their ‘millets’, not as equal citizens, but as ‘dhimmis’ (protected minorities).

Having once championed the establishment of a full-fledged Islamic state, the PAS now demands at least expanding Sharia law and elevating the status of the Syariah court system, which now has limited jurisdiction over Muslims’ personal and family matters, to that of the civil courts. As the PAS’s brand of Muslim religious nationalism has increasingly overridden the UMNO’s Malay ethno-nationalism, these goals have gained the support of a growing number of Muslims.

While not known to be religious, Mahathir shrewdly co-opted Hadi’s more charismatic and visionary contemporary, Anwar Ibrahim, in 1982 to spearhead the UMNO’s own Islamisation projects. From Islamic higher education to Islamic banking to religious bureaucracy, Mahathir and Anwar stole the PAS’s religious thunder—that is, until the UMNO split. In 1998, Mahathir imprisoned Anwar, who had tried to replace him. After that, the PAS absorbed many of Anwar’s followers, expanding its influence from its stronghold in the north to the entire country.

Since the 2013 election, when Najib lost the popular vote but clung to power thanks to electoral gerrymandering, he has worked to bring Hadi on side, for example, by facilitating the potential introduction of harsh hudud punishments (mandated by God under Islamic law) for crimes like adultery, drinking and apostasy. It was a Machiavellian masterstroke that not only drew the PAS out of the opposition coalition, but also led Hadi to defend the scandal-plagued Najib.

The PAS has announced plans to contest about 60% of parliamentary constituencies. This may siphon Malay votes from PH, giving the UMNO many narrow victories. If the turnout among Malays is low, PH will suffer more than Najib, who could end up winning more seats with even fewer votes than in 2013.

As for the PAS, its continued political relevance hinges on eliminating the threat posed by Mahathir and its own splinter party, Amanah, formed by pro-Anwar moderates. If Mahathir cannot secure one-third of the seats in parliament, the PAS can claim that it is indispensable, even if it loses every constituency. In such a scenario, no Malay opposition leader would dare denounce the PAS’s Muslim nationalism. The UMNO, despite its electoral victory, would have even less of the moral courage needed to block the PAS agenda.

If Mahathir does secure one-third of the parliament, Malaysian politics will undergo significant changes, even if the UMNO remains technically in charge. If Amanah can supplant the PAS as the main Islamic party, the trend toward religious extremism would likely be reversed. And if the PPBM is established as a rival defender of Malays’ favoured status, the UMNO would lose its monopoly on the issue, making Malay politics more competitive.

So far, Malaysia’s nonagenarian comeback kid has been making inroads in many UMNO and PAS constituencies. But Malays alone will not decide the outcome of his battle with the PAS and Najib. As many marginal constituencies are ethnically mixed, low turnout among non-Malays may help the PAS—and hurt Malaysia.