In the run up to the British general election in May David Cameron has accused the Labour Party of planning a post-election coalition with the Scottish National Party in order to form the next government together. As the Economist magazine noted ("Downtrodden Labour: Why Conservatives are talking up a Labour-SNP coalition" March 14, 2014) this charge is denied by Labour leaders but not dismissed; the SNP is like to win several constituencies now held by Labour and Labour leader Ed Milliband will need them to replace Cameron as prime minister.
Cameron's strategy resembles the one employed by Canadian Prime Minister Stephen Harper in 2008. Harper's Conservatives went into that election as a minority government (that is, with more seats in the House of Commons than any other party, but short of a majority). The opposition was led by Stéphane Dion, head of Canada's Liberal Party. Two other parties held seats in Parliament: the New Democratic Party and the Bloc Québécois, both social democratic parties. This made it unlikely that either party would cooperate with Harper's Conservative Party to form a government after the election.
During the election campaign, Harper accused the Liberals of plotting to form a government with support from the separatist Bloc Québécois. The Liberals traditionally drew more support in Quebec than any other federal party, just as Labour has in Scotland.
Harper's charge put Dion in a precarious position. Distancing the Liberals from the separatist Bloc Québécois would risk alienating Quebec voters that he would need to win an election. Yet denying that he would cooperate with the Bloc Québécois would damage Liberal support in the rest of Canada, where patriotic hostility to Quebec separatism was powerful after two unsuccessful independence referenda in Quebec and more than three decades of constitutional discussions launched to respond to Quebec nationalism.
Although many Liberals and media pundits recognized the trap Harper has set, Dion walked into it. He announced a coalition plan with the NDP, but demurred that the Bloc Québécois support needed to form government would be informal cooperation short of a coalition government.
The election saw Conservatives win 143 of the seats in the House of Commons, enough to keep Harper in power as head of a minority government. Quebec voters surprised observers by throwing support to NDP candidates, indicating in exit polls their disaffection for both the Conservatives and the Liberals. The Bloc Québécois, with weak leadership, lost seats.
British voters may react similarly in 2015. Cameron may bolster his support outside Scotland by positioning himself as the champion of national unity and the United Kingdom even as he alienates Scottish voters. And it appears that Milliband may walk into Cameron's trap as maladroitly as Dion did Harper's. It may even be the case that the Liberal Democrats win surprising support in Scotland from voters dismayed at the Conservative ploy and the Labour waffle.
In Canada, Stephen Harper led two minority governments before his 2011 win gave him a solid majority. Britain's David Cameron became prime minister in 2010 by virtue of a coalition with the Liberal Democrats and would clearly prefer a majority of his own. By imitating Harper's Canadian Crunch, he may have improved his chances.
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