Regrettably, Canadian general elections get only a fraction of the attention that is routinely lavished on contests in their more powerful neighbour to the south. Yet the Liberal win in Monday’s election is highly significant. It marks a big political shift to the centre-left in a crucial G7 power, and the victory of Canada’s Liberals also has lessons for politics across the developed world.

When the now-defeated Conservative prime minister Stephen Harper called this week’s election at the start of August he made the same kind of bet that David Cameron successfully relied on in May’s UK contest. Inequality had risen and economic growth was stuttering, but Mr Harper gambled that he could win a rare fourth term by relying on his party’s economic record, cutting the federal government, the inexperience of his opponents and by ruthless use of negative campaigning and wedge issues like a ban on the niqab at citizenship ceremonies.

As the 11-week campaign unfolded, however, Mr Harper found that voters were not buying what he tried to sell and, crucially, that there was also an alternative they were prepared to trust. Although the three main parties – the ruling Conservatives, the former governing Liberals and the leftwing New Democrats – ran neck and neck for some weeks, in the last month the Liberals moved ahead of the pack, with the NDP slumping. On Monday, the results exceeded most forecasts, with the first-past-the-post system handing the Liberals’ Justin Trudeau a 30-seat overall majority in Ottawa on the basis of 39.5% nationwide support, moving the party from third place last time to winners now.

It is hardly surprising that Canadians have voted for change rather than more of the same. Mr Harper’s vindictive and divisive style, his addiction to shrinking the government, his authoritarian tendencies and his failure to offer anything new this time after a contentious if successful decade in office had clearly run their course. One in three Canadians continued to back Mr Harper all the same. But the two in three who wanted rid of him finally gathered behind Mr Trudeau and sent NDP hopes of heading Canada’s first leftwing government of modern times back to the drawing board.

Early in the campaign, Conservative attack ads depicted the 43-year-old Mr Trudeau as “just not ready”. But strong debate performances, a positive campaign message and an unwillingness to be shackled by Conservative deficit-reduction plans – the new government promises to run small deficits in the next three years – handed the Liberals an initiative that would have seemed hard to credit after the debacle of 2011. The Trudeau name proved to be a plus, not a minus.

Mr Trudeau offers a very different kind of Canada. This will have international implications too, on subjects including climate change, Syria and Ukraine. But the Harper decade has rewired Canada in countless ways, from fiscal policy to defence, some of which will survive. Like all incoming reformers, Mr Trudeau will have to pick his priorities. Simply going back to the kind of Liberal offer that marked the party’s 1990s ascendancy could be both expensive and foolish. Subjects like health, urban affairs and the environment, which Mr Harper trampled on or ignored, may prove to be the right new priorities for a government whose election is good news at home and abroad.