THE Liberal Party of Canada took a gamble on April 14th and selected Justin Trudeau, the 41-year-old son of a former prime minister, as its leader. Mr Trudeau was the runaway favourite in a field of six candidates, taking almost 25,000 of the 30,800 points available in a vote by preferential ballot. Judging from the repeated rounds of applause during Mr Trudeau’s acceptance speech, the boisterous Liberals gathered in the ballroom of an Ottawa hotel were certain they had made the right choice.

The Liberals ruled Canada for much of the 20th century but have been in the political wilderness since losing power to Stephen Harper’s Conservatives in 2006. They currently hold third-party status. Mr Trudeau’s job is to return the Liberals to the power that they enjoyed under his father, Pierre Trudeau, who was prime minister for most of a 16-year stretch from 1968 to 1984. Trudeau père was a charismatic figure who drew comparisons to John F. Kennedy. His son has inherited the famous name and handsome face. Will he have the same success?

Mr Trudeau’s current popularity must be weighed against his relative lack of political experience and the absence of a detailed policy platform. He worked as a secondary-school teacher in Vancouver until 2008, when he won a difficult seat in Montreal. He has used only broad strokes to outline his policies so far, preferring to wait until closer the next general election, expected in 2015, to fill in the details.

Neither of these shortcomings need prove fatal. His famous father had been in the House of Commons for only three years, albeit as a minister, when he became party leader 45 years ago. Trudeau Jr.’s avoidance of detailed policy commitments has the advantage of giving the Conservatives less material to feed into their attack ads, which they used to devastating effect against the previous two Liberal leaders.

Mr Trudeau’s views on how to deal with those anticipated attacks represent a departure from politics as usual. Canadians, he said in his acceptance speech, are tired of negative, divisive politics and want the Liberals to rediscover the “sunny ways” of Wilfrid Laurier, a former Liberal prime minister who favoured persuasion over confrontation. This has got some party insiders worrying about the consequences. One of them asks:  “When the Conservatives unleash the dogs of war, are they going to tear him apart?”

Despite those misgivings, the Liberals have little to lose and much to gain by gambling on Mr Trudeau. The party’s fortunes have steadily declined under the previous three leaders. The Liberals slipped from majority to minority government and then defeat under Paul Martin in 2006. Two years later under Stéphane Dion they had their worst showing since Canada became a country. In 2011, under Michael Ignatieff, they slipped to an ignominious third place in the House of Commons.  In an indication of how much that final humiliation still stings, the words “Michael Ignatieff” did not pass anyone’s lips at Sunday’s party convention, which he did not attend (though he did feature briefly in a video of past leaders).

The latest poll, done before the leadership was decided, had the Liberals leading the Conservatives, with the New Democrats in third place. This could be the usual bump in public esteem parties get during a leadership contest. The Liberals experienced something similar after first Mr Dion and then Mr Ignatieff won the top job. Or it could signal something more permanent.

Mr Harper and his Conservatives are now in their seventh year in office and are accumulating the baggage of a government showing its age. Two ministers have stepped down this year following lobbying and campaign-spending scandals. The economy, which the public sees as the Conservatives’ strong point, is barely growing. The March jobs-report was a disaster, with employment declining by 55,000 and the unemployment rate climbing 0.2 percentage points to 7.2%. The Conservatives’ single-minded focus on eliminating the budget deficit by 2015 has left them open to the charge that they are bereft of new ideas and have run out of puff. Disenchantment with the government is growing.

Still, it is not just the Conservatives that Mr Trudeau and the Liberals are up against. The New Democrats, under Thomas Mulcair, are the official opposition and are trying hard to present themselves as a government-in-waiting. At their policy convention in Montreal, which ended on the same day that Mr Trudeau won the Liberal leadership, they agreed to take references to socialism out of the party constitution, one of a number of moves to position the party as more moderate.

That’s a start. But Mr Mulcair seems to inspire voters less than either Mr Trudeau or Mr Harper. Pollsters say that voters see him as competent but grumpy. The party is said to be working on giving him a softer image. But no amount of soft soaping by party officials can change the fact that both he and Mr Harper look old and staid compared with the youthful Mr Trudeau. That is just what the Liberals are counting on.