Justin Trudeau's Liberals won't be facing the electorate in 2018, but two of their key provincial allies will. If Ontario Premier Kathleen Wynne and Quebec Premier Philippe Couillard meet their political ends this year, it could prove to be an annus horribilis for the Liberals.

The links between Trudeau's entourage and Queen's Park, where the Liberals have held power since 2003, run deep, and Wynne is the closest ally the federal government has among the provincial premiers. Couillard is one of the most federalist premiers in Quebec's history.

Both face long re-election odds. The polls suggest they are on track to be replaced by figures on the centre-right.

Neither Patrick Brown, leader of the Ontario Progressive Conservatives, nor François Legault, head of Coalition Avenir Québec, is a particularly strident opponent of the Trudeau government. But losing the familial links the prime minister has with the two most powerful premiers in the country could inject a dose of unpredictability into federal-provincial relations.

Other Canadian elections may not prove as problematic. Brian Gallant, another close ally of the Trudeau Liberals, is leading the polls in New Brunswick and looks set to secure re-election in September. Municipal elections in Ontario are also likely to return friendly mayors like John Tory in Toronto and Jim Watson in Ottawa.

But the Liberals have not had to get used to defeats since Trudeau won the federal leadership in 2013. Provincial Liberals took power in Nova Scotia in 2013, New Brunswick and Quebec in 2014 and Newfoundland and Labrador in 2015.

Wynne's Liberals were elevated from a minority to a majority government in 2014, and the Liberals were re-elected in Prince Edward Island in 2015.

The Conservatives had a better run in 2016, when Brad Wall's conservative Saskatchewan Party was re-elected and Brian Pallister's PCs took office in Manitoba. The past year has been mixed for the Liberals, who did see Nova Scotia Premier Stephen McNeil re-elected but saw the defeat of a sometimes-ally in British Columbia when Christy Clark was ousted by an alliance of New Democrats and Greens.

Will 2018 return to a year of victories for the Liberals, or will the provincial landscape get a lot more complicated — and a lot more blue?

Brown's election to lose in Ontario

The polls in Ontario disagree on whether Wynne is on track for a catastrophic defeat or just a difficult re-election challenge. But there is no doubt she is in some trouble. She has the lowest approval ratings of any premier in the country and has trailed the PCs in most polls in 2017.

The election is going to be Brown's to lose. In the June vote, he will be up against a deeply unpopular premier and a party that will have been in power for nearly 15 years. This will make it tough for Trudeau's closest ally to mount a comeback.

Ontario Progressive Conservative Leader Patrick Brown is leading in most polls. (Chris Young/Canadian Press)

But the PCs recently came forward with a centrist campaign platform that sounds Trudeauesque in some regards — it calls for deficit spending, progressive child care credits and a carbon tax.

While Trudeau and Brown may be able to find some common ground on particular issues, another conservative around the premiers' table will inevitably cause more problems for the Liberal prime minister.

Federalist red to nationalist blue in Quebec?

In Quebec's October election, Couillard may also struggle to extend the life of his government. The Liberals have run Quebec for all but two of the last 14 years and are trailing the CAQ in the polls.

The ouster of the Quebec Liberals would normally set the country down the path of a national unity crisis. But support for the Parti Québécois is in free fall. Instead, the CAQ would push for more powers for Quebec within Confederation.

Coalition Avenir Québec Leader François Legault is leading the polls as Quebecers' choice for premier. (Jacques Boissinot/Canadian Press)

How Legault would react if these demands are rebuffed is unknown, adding another element of unpredictability to the federal-provincial relationship.

Quebec is a key province in the federal Liberals' 2019 re-election strategy. With Couillard at the helm, the Liberals do not need to worry too much about the potential for a spike in nationalist fervour. Legault would make Quebec more of a wild card.

Comebacks still possible

Though the deck looks stacked against Trudeau's Liberal allies in Ontario and Quebec, Wynne and Couillard do have plausible paths to re-election.

In Ontario, the Tories went into the 2011 and 2014 campaigns with leads in the polls before their own policies and the performance of leader Tim Hudak undercut their chances. Brown remains largely unknown to Ontarians. Once the campaign begins, voters may decide they do not like what they see in the PC leader.

Wynne would still need to ensure that support does not bypass her and go over to Andrea Horwath's NDP, but the potential for another Liberal comeback in Ontario cannot be discounted.

The CAQ has led the polls in Quebec before. It was the most popular party in the province less than a year before it finished third in the 2012 provincial election.

Legault has already led the CAQ through two election campaigns without a breakthrough. The party has never governed, and voters may decide not to give his inexperienced team the keys to the premier's office, particularly when Quebec's economy is one of the best performing in the country.

It is not out of the question that one of these two embattled premiers could manage to mount a comeback. If both pull off the feat, that could turn the Liberals' 2018 into an annus mirabilis.