In 1998 Michael Ignatieff, the Canadian Liberal party leader and former globetrotting academic, said that he voted Labour in Britain's 1997election to oust the Conservatives – or in his own words, "to get the rascals out". It is looking increasingly unlikely that after the 2 May general election in Canada, Ignatieff will be able to repeat the same boast.

The Liberal campaign hardly got off to a good start, with Ignatieff's declaration that he wouldn't seek a coalition after the vote implying that the Liberals weren't interested in governing. It is the latest furore over the Liberal leader's voting record, however, that not only has the potential to hand victory to Stephen Harper's Conservatives, but also underlines the social and cultural malaise that has taken hold in the half decade of Harper's leadership.

It bears all the hallmarks of an embarrassing, if harmless political gaffe: a poorly briefed Liberal party press officer was caught off-guard by a tabloid reporter's questions on whether Ignatieff, who spent long stints in the UK and the US, had ever voted in another country's elections. On the defensive, the staffer issued a flat denial, at which point the Toronto Sun gleefully printed the above quote, along with another from a 2004 interview with Glasgow's Herald endorsing John Kerry for the US presidency, and records showing Ignatieff was registered to vote in the UK as recently as 2002.

The Liberal leader has since set the record straight, but the episode has played directly into his Conservative opponents' hands. The Tories have long since run suggestive ads questioning the depth of Ignatieff's Canadian identity. Helped by press coverage of the latest Liberal pratfall, the mud clings when the Tories tell voters "he didn't come back for you". The slur is aimed more at Ignatieff's identity as an upper middle-class urban intellectual rather than his Russian origins. However, this level of jingoism betrays a society ill at ease with its own diversity, where an attack on internationalism and ambition – after all, that is what Ignatieff is being accused of – has traction with culturally isolated voters.

The current Liberal leader has none of the charisma of his internationalist predecessor, Pierre Trudeau, or the down-home accessibility of his Conservative opponent. Indeed, in the personality stakes, the debonair leader of the nationalist Bloc Quebecois, Gilles Duceppe, eclipses both. So while Ignatieff struggles to shed his image as an aloof academic, the Conservatives merely have to release a steady stream of images of Harper, the "real" Canadian, to drive the message home: shaking hands at a Tim Hortons coffee shop in Niagara; or playing a pickup hockey game with local kids in Ottawa. It's working: the latest opinion poll puts the Conservatives 11 points ahead nationally, and 3% up on their 2008 election result. This election marks Harper's best chance of securing the majority government that has eluded him since he became prime minister in 2006

Modern Canada seems to be retreating in on itself, clinging to the security of its own cultural stereotypes. The coincidence with Harper's leadership is difficult to escape; George Monbiot wrote powerfully in 2009 that the Conservative environmental policy had seen Canada degenerate into a "thuggish petro-state". His only inaccuracy was not seeing just how far that transformation had gone. In 21st- century Canada a Conservative incumbent candidate in Calgary can attack his Liberal opponent as being a "visitor from Toronto" simply because she attended university there – despite the fact they are both of immigrant origin. A Pakistani-born commentator can plough a furrow through the public debate, warning of the danger of radical Islamism in a country with a Muslim community making up just 2% of the total population.

This isn't George W Bush's America, this is Canada, today. It seems ludicrous, in a country that has participated in every UN peacekeeping mission in history; one whose last governor general was a Haitian refugee-turned-journalist. There is seemingly no reason for a flight to monolithic cultural values, with Canada weathering the economic storm far better than most developed countries. However, far from being comforted by economic prosperity, in the past decade Canadians have become more afraid of one another, to the extent that even lost boys like Omar Khadr and far-left pin-ups like George Galloway are deemed toxic national threats.

As a result Canada now lacks the cultural confidence to meet news of Ignatieff's foreign votes with the only reasonable response: "what of it?"