Canada Liberal leader Trudeau looks to prove himself in debate

Liberal leader Justin Trudeau speaks as he campaigns in Mississauga, August 4, 2015. Canadians will go to the polls for a federal election on October 19. REUTERS/Mark Blinch

By Randall Palmer and David Ljunggren OTTAWA (Reuters) - Liberal leader Justin Trudeau, who won headlines in 2012 by whipping a Conservative senator in a charity boxing match, will try to prove he's a heavyweight in the political arena in Canada's first electoral debate on Thursday. The 43-year-old Trudeau, who has fallen to third from first in the polls, will face three-term Conservative Prime Minister Stephen Harper, 56, as well as 60-year-old Thomas Mulcair, leader of the New Democratic Party. The debate will have to vie for attention with Donald Trump and the U.S. Republican primary debate on the same night. Polls show Mulcair has displaced Trudeau as the main challenger to Harper in the run-up to the Oct. 19 vote amid questions over whether the Liberal leader with boyish looks has the experience to head Canada's federal government. Both Harper and Mulcair, a former provincial cabinet minister in Quebec, have taken swipes at Trudeau saying the job of prime minister is not an entry-level position. Trudeau, who enjoys wide name recognition as the son of former Prime Minister Pierre Trudeau, worked as a teacher before being elected to Parliament in 2008. "The guy who has to really kind of change the narrative is Justin Trudeau," said Ipsos Public Affairs pollster Darrell Bricker. "His problem is demonstrating the opposite of what the Conservative ads have been saying, which is proving that he actually is ready." The Conservatives, who have run ads for months charging Trudeau is "just not ready," suggested he would just have to turn up for the two-hour debate in Toronto to be considered a success. "The bar for Justin has been set so low he can't help but surpass expectations," said Conservative campaign spokesman Kory Teneycke. Trudeau tried to revive some fighting spirit by scheduling a visit to a Toronto boxing gym on Thursday before the debate. "He will have the opportunity to speak directly to Canadians about his plan to grow the economy by strengthening the middle class," said Liberal spokesman Cameron Ahmad. Mulcair spokesman Shawn Dearn was less impressed, tweeting: "Trotting out one's leader to flash some skin at gym before debate smells of desperation." Bricker said Mulcair, the country's official opposition leader, should be in a venue that favors him given his ability to get under Harper's skin in toe-to-toe encounters in the House of Commons. A veteran debater, Harper is expected to stick to his strategy of stressing his experience and attacking rivals as risky. Green leader Elizabeth May will also take part in the debate, which starts at 8 p.m. ET (0000 GMT). (Editing by Jeffrey Hodgson and Alan Crosby)