Both the Conservatives and New Democrats will choose new leaders in 2017, but the Liberals will also have some important decisions to make, including how to handle the prime minister's ongoing fundraising controversy and whether to move forward with electoral reform.

Here are five federal politicians to watch this year.

Prime Minister Justin Trudeau

Though the prime minister is always the most important political figure in the country, Justin Trudeau carries his party more than most leaders. He is hyper-present, making himself the face of the government and the controversial decisions it makes — as he did when he announced the government's decision on oil pipelines in November rather than passing the responsibility to Natural Resources Minister Jim Carr.

Trudeau is more popular than his party, with an approval rating averaging 59 per cent in 2016, while the Liberals averaged 47 per cent support.

But his numbers dipped as the year came to a close and the controversy surrounding "cash-for-access" fundraisers may be contributing to that.

A recent Nanos Research poll suggested 62 per cent of Canadians disapprove or somewhat disapprove of elected officials attending $1,500-per-ticket fundraising events, while Abacus Data found the controversy has made Canadians feel worse rather than better about the Trudeau government by a margin of three to one.

Being the headliner for these events, while also being the face of the Liberal Party, may prove to be an enduring problem for Trudeau in 2017.

Democratic Institutions Minister Maryam Monsef

It will be up to Democratic Institutions Minister Maryam Monsef to deliver on the Liberals' promise of electoral reform. (Sean Kilpatrick/Canadian Press)

The Liberals campaigned on ending the first-past-the-post voting system before the 2019 federal election and it's up to Maryam Monsef, minister of democratic institutions, to deliver on that promise.

Despite a palpable lack of enthusiasm on the part of the Liberals for either proportional representation or a referendum on any change to the electoral system — the two main recommendations of the special committee on electoral reform — Monsef still promises to present legislation in the spring.

Polls don't suggest Canadians are convinced there's a need to change the electoral system and they're even more divided on what kind of change should be enacted. They are clearer on whether a referendum should be held: according to a recent Forum poll, 64 per cent of Canadians, including 55 per cent of Liberal voters, said there should be a vote.

Monsef's move on electoral reform will affect every MP in the House of Commons, so the legislation she says she'll present in the spring has the potential to be one of the most consequential bills of the entire year.

NDP MP Nathan Cullen

NDP MP Nathan Cullen could have a big impact on the NDP leadership race — even though he's not running. (Adrian Wyld/Canadian Press)

British Columbia MP Nathan Cullen is the NDP's critic for democratic reform and an outspoken proponent of proportional representation. With every step that Monsef takes on this file, Cullen will be right there to challenge her.

Cullen will also likely have influence on the NDP's leadership race. Cullen, who finished third in the party's 2012 leadership campaign, has already ruled himself out this time. But his endorsement might be the most valuable from any New Democrat.

Conservative MP Kellie Leitch​

How Kellie Leitch fares in the Conservative leadership race could influence where the party goes from here. (Liam Richards/Canadian Press)

Whether Ontario MP Kellie Leitch succeeds or fails in her bid for the Conservative leadership will only tell part of the story of what her populist campaign means for the future of her party.

Can she win? So far, she has few endorsements from fellow caucus members or party luminaries, she was beaten by Quebec MP Maxime Bernier in fundraising in the third quarter of 2016, and the rules of the leadership race reward contestants with a broad base of support — a base that her fundraising data suggests she doesn't have.

But if Leitch wins, she would pull the Conservatives in a direction that would leave Trudeau's Liberals with a lot of room in the centre of the political spectrum — and polling suggests the Liberals are already holding a wide lead among centrist voters.

If Leitch loses, the scale of that defeat could also have an impact on the future of the party. If she takes a large share of the vote, the next leader of the Conservatives might feel the need to take up some of Leitch's policies, which include screening immigrants for "anti-Canadian values" and dismantling the CBC. But if she wins a small share of the vote, it could be an indication that populism doesn't work in Canada.

'Consensus' candidate for Conservative leader

No clear front-runner has emerged in the crowded Conservative leadership race. (Andrew Vaughan/Canadian Press)

Considering there is no apparent front-runner yet in the crowded Conservative leadership race, there is a significant likelihood that the eventual winner could be the contestant who finishes second or third on the first ballot.

With their unique policy positions, candidates like Michael Chong, Leitch and Bernier might occupy a large enough section of the Conservative membership base to do well on the first ballot, but they could have trouble garnering the second- and third-choice votes needed to win. That opens up the door to "consensus" candidates, those who are trying to alienate the fewest number of members by avoiding controversial policies — candidates like Andrew Scheer, Erin O'Toole and Lisa Raitt.

The long list of contestants and the lack of hard data on their rankings in the race make it impossible to know who that consensus candidate might be just yet. Data, such as fundraising numbers and polls on second choice preferences, might help clarify things before party members vote in May.

But until the list of contestants is winnowed down, it might be difficult for any candidate to stand out from the pack.