Malaysians began voting on Wednesday in what is likely to be the country’s closest-fought general election, with Prime Minister Najib Razak’s coalition pitted against a resurgent opposition steered by 92-year-old former leader Mahathir Mohamad.

Najib’s long-ruling Barisan Nasional (BN) is expected to win despite an election-eve opinion poll suggesting that its support was slipping and that Mahathir’s alliance would land more votes in peninsular Malaysia, home to 80 percent of the population.

Under Malaysia’s first-past-the-post system, the party or alliance with the majority of seats in the 222-member parliament wins. Most experts believe that is within Najib’s reach despite popular anger over a multi-billion-dollar graft scandal that has dogged him since 2015 and increased costs of living.

“I think right now, it looks more favorable to BN, as they are able to pull in most of east Malaysia,” said Mohamed Nawab Mohamed Osman, a Malaysia scholar at the S. Rajaratnam School of International Studies in Singapore. “However, the margin that we’re talking about is very small.”