After an 11-week campaign, Canadians head to the polls Monday to choose their local representative. The party that wins the most seats will be offered the first opportunity to form the government, with that party’s leader named prime minister.

However, if no party wins a majority of seats, Canada could see some wrangling by the political parties to determine who will actually govern.

Stephen Harper, Conservative Party​

Stephen Harper is the incumbent head of Canada’s government. He was first elected prime minister in 2006, when his party won a plurality of seats, allowing it to form a minority government and oust the Liberal Party after 12 years in power.

Under Harper, the Conservatives were re-elected in 2008 and in 2011, finally securing a majority in the latter election. That meant the party could pass legislation without needing the support of other parties.

Harper’s administration has been defined by a hard shift to the right in a country that had been known for its liberal politics, as well as a number of high-profile scandals.

Harper has presided over an economy that has suffered as result of the global economic crisis and, more recently, the downturn in the price of oil. He has repeatedly stressed his support for Canada’s controversial oil sands projects in Alberta, Harper’s home province. The oil there is a heavy crude that is expensive to extract. When the price of oil falls, it is no longer profitable.

Canada’s largest private-sector union, Unifor, released a study in July 2015 that determined Harper had the worst job-creation record of any prime minister since World War II.

Nonetheless, the Conservatives initially designed their latest campaign around their party being the best positioned to protect the country’s economy. Amid flagging support, however, the party shifted tactics and began engaging in fear-mongering about Muslims.

The tactic was effective, with the question of whether women should be allowed to wear a niqab when taking their citizenship oath becoming the number one topic of debate for several weeks. This served to change to tone of the campaign, which had previously been focused on substantive issues, such as Canada’s refugee policy. This became a big topic after it emerged that the family of Alan Kurdi — the young boy whose body washed up on a shore in Turkey — had been trying to make it to Canada before the boy’s death fleeing the conflict in Syria.

On the topic of immigration, the Conservative government under Harper has made permanent immigration to Canada a much more difficult affair, placing greater emphasis on temporary foreign workers.

The Harper government has also been the target of heavy criticism from environmental groups, particularly over its support for oil sands. Harper has deliberately tried to silence his critics on this issue, even muzzling scientists on the public payroll. During Harper’s tenure, Canada’s tax agency has also targeted charitable agencies, particularly those with an environmental focus, for allegedly engaging in political advocacy.

The Conservative government has also been characterized by scandal. A number of Harper-appointed senators, who form Canada’s unelected upper house, are under investigation by police. Some have been charged with crimes, such as Patrick Brazeau, who faces charges of breach of trust and fraud.

Conservative Senator Mike Duffy is also currently on trial over 31 charges, mostly related to allegations of bribery. Part of his trial overlapped with the beginning of this year’s campaign, generating a number of embarrassing headlines for his party.

Harper also faced heavy criticism over a highly controversial anti-terrorism bill that critics said was too far-reaching, having dramatically increased the powers of Canada's spy agency.

After nearly a decade in power, polls have consistently shown that Canadians are interested in a change in leadership. Thanks to Canada’s first-past-the-post electoral system, however, Harper’s Conservatives still stand a chance of remaining in power.

Tom Mulcair, New Democratic Party

Mulcair is the leader of Canada’s official opposition, a left-of-center New Democratic Party, which, like the Labour Party in the United Kingdom, is supported by organized labor.

This is Mulcair’s first election as the head of the NDP. He was previously a member of the Liberal party in the province of Quebec, where he served in the cabinet of a center-right premier, Jean Charest. Mulcair eventually broke away from Charest over disagreements on environment policy and was subsequently recruited to the NDP by the late Jack Layton, who passed away from cancer in 2011 shortly after the last election.

Normally consigned to third party status, the NDP leapt to second place in 2011 under Layton’s leadership, with a record breakthrough Quebec. This election is seen as the best opportunity for the party to form the government. Until now, Canada has always been ruled by either Conservatives or Liberals.

Until recently, the NDP was polling in first place, driven in large part by Mulcair’s performance as opposition leader and, specifically, his rejection of a controversial anti-terror law.

But the party opted for the front-runner strategy of playing it safe, mostly focusing on trying to paint Mulcair as ready to govern. It also began making tepid promises that alienated its left-wing base, including a pledge to not run budget deficits if elected.

Mulcair sought to present himself as the candidate of change, hoping to marginalize the leader of the Liberal Party and turn the election into a two-horse race between the NDP and the Conservatives.

Pundits have criticized this strategy, arguing it exposed the party to attacks from its left by the Liberal Party and its leader, Justin Trudeau, whose performance in this election has exceeded expectations. The NDP is now polling in third place.

Justin Trudeau, Liberal Party

Trudeau is best known for being the son of a former Liberal prime minister, Pierre Trudeau, who served as Canada’s head of state on two separate occasions for a total of 15 years.

At 43, Trudeau is the youngest of the party leaders. That led to accusations by his opponents that he is too inexperienced for the post of prime minister.

Many of the Conservative’s attack ads have focused on that alleged inexperience. Ahead of the first debate, for instance, Stephen Harper’s spokesperson said that if Trudeau came out on stage with his pants on he would “probably exceed expectations.” But the comment had the opposite effect, allowing Trudeau to exceed exceptionally low expectations.

The Liberal Party has deliberately run a campaign based on their leader’s personal image. Trudeau has employed a tried and true Liberal strategy of campaigning on leftist rhetoric, promising large investments in infrastructure, pledging to raise taxes on the wealthy, and committing to deficit spending.

However, Trudeau has also been heavily criticized for supporting Harper’s anti-terror law and for what some see as his empty rhetoric on the campaign trail related to the needs of Canada’s middle-class.

Trudeau’s strategy appears to be working, though, with Liberals now polling in first place and poised to form, at the very least, a minority government.

Trudeau’s opponents had been counting on him to commit gaffes on the campaign, which the young leader has largely managed to avoid.

Still, the party was rocked after its national campaign co-chairman, Dan Gagnier, was recently forced to step down after he was found to have given inappropriate lobbying advice to Canadian energy company. That has had the effect of reminding the Canadian public of the Liberal Party’s record in power: it lost control of the government to the Conservatives in 2006 after a string of corruption scandals.