OTTAWA -- Ukraine's prime minister is in Ottawa Tuesday for what's likely to be the last visit by a foreign government leader ahead of this fall's federal election.

Prime Minister Stephen Harper will be meeting with Arseniy Yatsenyuk to sign a trade deal, following Yatsenyuk's visit to the U.S. Monday.

The stakes, for Harper, are more than just commercial.

While getting photos of themselves with foreign leaders who have strong diaspora communities in Canada is part of every candidate's toolbox, some critics argue that the Conservatives' entire foreign policy approach to Ukraine is connected to courting voters among the 1.2 million people who identify as Ukrainian in Canada.

Leaked campaign documents ahead of the 2011 election suggested the Conservatives were actively wooing the Ukrainian-Canadian vote and the plan doesn't appear to have changed.

A riding whose Ukrainian-Canadian community was explicitly targeted in 2011 was Etobicoke Centre, which the Conservatives won from the Liberals after a fight that went all the way to the Supreme Court.

In a recent interview with the Ukrainian publication Meest, the Tory MP for the riding Ted Opitz used a discussion of his party's policy on Ukraine to make a dig at Liberal Leader Justin Trudeau.

Trudeau was forced to apologize last year after making a joke that appeared to make light of Russia's activities.

But many of the ridings that are home to significant Ukrainian-Canadian communities have been Conservative strongholds long before the Russian annexation of Crimea kickstarted a global response that included Canadian military and aid support.

And in others, it's not the Liberals in second place but the New Democrats.

That may explain why NDP leader Tom Mulcair has not spoken up much in the House of Commons on the substance of Canada's approach to Ukraine, largely leaving those duties to his foreign affairs critic Paul Dewar.

Here's a look at some of the ridings where Canada's approach to Ukraine could be a ballot box question.

Manitoba

Riding: Elmwood-Transcona

Ukrainians as percentage of population: 20.8 per cent

State of play: The Winnipeg-area riding had been held by the New Democrats for nearly three decades but the Conservatives eked out an exceptionally narrow victory in 2011 with candidate Lawrence Toet, who captured the riding by a margin of only 300 votes.

Toet is running for re-election this fall but he is facing off against a well-known name in the area.

The NDP challenger is Daniel Blaikie, whose father Bill was Elmwood-Transcona's MP for two decades before he retired from federal politics.

Daniel Blaikie's sister Rebecca is the president of the NDP.

Saskatchewan

Riding: Yorkton-Melville

Ukrainian population as percentage of population: 27.9 per cent

State of play: This is the riding with the largest Ukrainian-Canadian population in the country. Conservative MP Garry Breitkreuz has represented it since 1993 when he defeated the NDP's Lorne Nystrom, who'd held the riding since the late 1960s.

The Tories have had a lock on the vote since Breitkreuz took over. In 2011 he got nearly 70 per cent of ballots cast.

Breitkreuz is not running for re-election. Replacing him is Cathay Wagantall, who had sought the Conservative nomination in Alberta in past elections but moved back to her home province of Saskatchewan in 2012.

Riding: Saskatoon-Grasswood

Ukrainians as percentage of population: 17.5 per cent

State of play: Longtime Conservative MP Lynne Yelich was seeking her party's nomination for this newly created riding, which takes in the urban parts of her old district, Blackstrap.

But Yelich lost to local sports broadcaster Kevin Waugh.

Still, the Conservatives have had comfortable margins of victory in the area, with New Democrats in second place. The NDP candidate is Scott Bell, who has practised aboriginal law with the federal government for 15 years.

Riding: Saskatoon West

Ukrainians as percentage of population: 14.8 per cent

State of play:This newly created riding is one the NDP has targeted for victory.

The party sees a seat there because the riding is largely urban, which is where most of its provincial support has been in recent elections.

The NDP candidate for the riding is Sherri Benson, a long-time community activist. The Conservatives are running city councillor and federal civil servant Randy Donauer and the Liberals are fielding Lisa Abbott, a lawyer who has also advised the Native Women's Association of Canada and the Assembly of First Nations.

Alberta

Riding: Edmonton Strathcona

Ukrainians as percentage of population: 13.4 per cent

State of Play:This riding has the distinction of being the only federal seat currently held by the New Democrats in the traditionally Conservative province of Alberta.

For decades this riding saw a three-way race in nearly every election, with both the Liberals and NDP competitive against the Tories until the 2006 campaign, when the NDP started gaining support.

In the 2008 campaign, Linda Duncan won the riding for the New Democrats by fewer than 500 votes, unseating Tory MP Rahim Jaffer.

In the 2011 campaign she increased her vote share, winning by more than 6,000 votes.

Lawyer Len Thom is running for the Conservatives and another lawyer, Eleanor Olszewski, is running for the Liberals.

Ontario

Riding: Etobicoke Centre

Percentage of Ukrainians: 7.4 per cent

State of Play:@ Though less influential in terms of size in this Toronto-area riding than electoral districts in western provinces, the Ukrainian-Canadians of Etobicoke Centre were targeted explicitly by the Conservatives in the 2011 election, according to campaign documents leaked to the media ahead of that vote.

The fight for the riding was so intense it wound up in Supreme Court, where justices quashed a lower court's call for a byelection on the basis of voting irregularities that saw Conservative candidate Ted Opitz win by only 26 votes.

The top court's ruling narrowed the margin further, leaving Opitz with a six-vote win over Liberal incumbent -- and Ukrainian-Canadian -- Borys Wrzesnewskyj.

Wrzesnewskyj is running again and in an interview with a Ukrainian-Canadian newspaper in late June said Canada needs to take even more of a leadership role in the Ukrainian crisis.

"So, at this critical juncture, we don't just need people that show respect to the community by showing up and saying all the right things, you need people that can work hard to make Canada make a difference in deeds," according to the article on the Novy Shliakh website.

"We have a special relationship with Ukraine, let's give it substance by showing leadership at this critical time."

Opitz, who is of Polish descent, has been the Conservatives' front man on all things Ukraine for months, and was one of 13 Canadians banned from travelling to Russia under retaliatory sanctions imposed by Russian President Vladimir Putin.