The surprise resignation of Portuguese Prime Minister Antonio Costa has kicked off what’s set to be a tight race between the senior figures in his party jostling to replace him and opposition leaders seeking to exploit the political turmoil from a probe into possible government corruption.

With an election scheduled for March 10, the challenge for Costa’s governing Socialists will be to hold onto votes amid the investigation, anger over housing, low wages and a previous pay controversy at state airline TAP SA.

They first must pick a new leader, with Costa, 62, saying he won’t stand again. Two current and one former minister could run. The leader of the center-right PSD, meanwhile, has said he’s ready to bid for the premiership.

The week of high political drama marks a watershed moment for Portugal. Costa, who’s been in the top job since 2015, was reelected at the start of last year with an absolute majority in parliament, ensuring backing for budgets. That meant he no longer needed to bargain with far-left parties to get support for legislation, like he did during his first two terms.

A majority administration is unlikely to be repeated, though, forcing the larger parties to try to govern with a minority in parliament, or to attempt coalitions that may seek concessions on such things as government spending.

Read More: Portugal Starts Election Countdown Amid Corruption Scandal

Interest rates have risen sharply in the last two years and the economy is cooling after a post-pandemic growth surge. The central bank sees growth of 2.1% this year and 1.5% in 2024, down from almost 7% in 2022.

The election won’t just be about the two main centrist parties. When Costa was reelected in January 2022, the far-right Chega party grew to 12 seats in parliament from one, becoming the third-biggest force. Opinion polls indicate support for that party has since increased further.

In a poll published on Friday, PSD had almost 22% backing, leading the Socialists by 3.9 percentage points. Chega had 13%, and the survey indicated 19% of voters were undecided.

Here’s a look at four potential candidates.

The Home Affairs Minister

Jose Luis Carneiro, 52, told reporters on Thursday night that he will run. He hasn’t been seen as a successor to Costa for as long as his two potential Socialist rivals.

His aim is “to guarantee safety, stability and investment in the improvement and deepening of policies that create more and better opportunities, and affirm Portugal as a country that can grow economically while always maintaining a great effort of social justice,” he said.

Heading the home affairs ministry can be a difficult cabinet post in Portugal, with responsibilities including overseeing firefighting resources and emergency services at a time when countries are facing hotter summers and bigger blazes. One of his predecessors resigned in 2017 after forest fires left more than 100 dead.

Carneiro has a degree in international relations and has worked as a university lecturer. He also served under Costa as secretary of state for Portuguese communities around the world.

The Former Minister

Pedro Nuno Santos is considered a likely successor to Costa. At 46, the economist is the youngest runner so far and is more willing to speak his mind than the other Socialist contenders. He’s also often linked to the left wing of the party and has been a defender of the state’s role in controlling certain businesses, including the national airline TAP.

He resigned as infrastructure and housing minister at the end of 2022 following criticism about the compensation paid earlier that year to a board member for leaving TAP, which received more than €2 billion ($2.1 billion) of government aid.

Santos recently became a political commentator for a television station, a step that could help bolster his popularity.

As secretary of state for parliamentary affairs from 2015 to 2019, he was the link between the minority Socialist government and the far-left parties that ensured Costa had majority backing in parliament. Costa said Santos had a “decisive contribution to create conditions of political stability.” That experience could be useful if the Socialists need support from other parties again after the election.

After graduating from university, he started working in his family’s industrial equipment business, called Grupo Tecmacal SA. He also led the Socialist Youth from 2004 to 2008.

The Finance Minister

Fernando Medina, 50, has always been in the mix to run the party. He’s an economist and was named to the post in March 2022 in a majority government that pledged budget discipline, together with further improvements in household incomes and investment in areas including health care and housing. Like Costa, he’s a former Lisbon mayor.

Medina has a long track record in government, having served as secretary of state for industry and for employment between 2005 and 2011. He was also an adviser to then-Prime Minister Antonio Guterres, now the United Nation’s secretary-general.

Keen on fiscal discipline, Medina aims to post a budget surplus of 0.8% of gross domestic product this year, which would be the biggest in Portugal’s last five decades as a democracy.

Even as the economy cools, his government has still been able to lower Portugal’s debt, which was the third-highest relative to GDP in the euro area in 2022.

The Opposition Party Leader

Luis Montenegro, also 50, is a lawyer and has led PSD since July 2022. Before then, he gained key experience during Portugal’s debt crisis. He was parliamentary party leader from 2011 to 2017, when his party was in government implementing a bailout program.

He faces an uphill task, though. Even as the Socialists struggled, opinion polls before the latest scandal suggested he wasn’t able to win supporters.

One selling point is tax. PSD has called for deeper tax cuts than the Socialists plan for 2024. While the economy has recovered from the Covid-19 pandemic, average wages remain low in Portugal, and PSD has also made that an issue. The party has highlighted that former communist countries like the Czech Republic have overtaken Portugal in terms of GDP per capita.

--With assistance from Gina Turner.