A guide to the leaders and their Achilles heels

Does Justin Trudeau have the chops to go toe-to-toe with Stephen Harper or is he, as the attack ad would have it, just not ready? Has Tom Mulcair, the House of Commons prosecutor-in-chief, been overrated? And does the Conservative leader, famously averse to improvisation, retain the flexibility, control and poise to trade barbs without coming off as mean or arrogant?

Though it comes at a time when many voters’ minds may be elsewhere, Thursday night’s Maclean’s debate is a pivotal moment in Campaign 2015. The reasons have less to do with policy, ostensibly the business at hand, than they do with personality, technology and the nature of modern politics. Here, then, is a handy look-ahead.

STEPHEN HARPER AND THE SARUMAN EFFECT

Harper enters the mosh pit with all the tools he needs to win. A veteran of televised leaders’ debates since 2004 and a policy wonk, Harper has facts at his fingertips and killer instinct to spare. He brings a clear assertion of conservative principles — public security, lower taxes, moral clarity on the world stage, a balanced budget — and an economic narrative that, for all its recent difficulties, compares decently with those of other leading industrial nations. Neither of his two principal foes has competed in a debate at anything approaching this level before. Therefore, the Conservative leader has to be counted the favourite at the mark.

That said, Harper has an Achilles heel: his highly competitive, partisan nature and his instinct for the cutting barb could make him appear the bully, reinforcing all his negatives. All it takes is one disrespectful, arch remark — as former Alberta premier Jim Prentice knows all too well — to cement the opposition story that Harper is aloof, complacent and arrogant, thanks to his 10-year stint in power. That’s why he’s likely to play this straight, avoiding any fireworks or attempted knockout blows, and wait for his opponents to make mistakes.

TOM MULCAIR, CARNIVAL BARKER?

The NDP leader is well-known for his prosecutorial acumen in the Commons, beginning in May of 2013 with the advent of the Mike Duffy Senate scandal. Like Harper, Mulcair has a reputation for being fiercely combative and clever: it’s how he made his case to become leader of his party in 2012, and how he has established himself as the NDP’s first serious contender for the keys to 24 Sussex. Mulcair is no slouch when it comes to the cutting remark; his ad libbed put-downs of Conservative Commons enforcers are legendary. And like Harper, he has a straightforward story to tell: he need only hammer the Senate spending scandal, the long list of Tory insiders who’ve run afoul of election and other laws to make his case for change.

Mulcair’s point of vulnerability: he has a tendency to rush when his dander is up. He and his handlers have spent the better part of a year dispelling his old reputation as “Angry Tom,” replacing it with a new image of him as grandfatherly but tough. Mulcair’s risk is that, particularly in engagements with Trudeau, he comes off as condescending or self-important. He also labours under the general perception that he’s a great rhetorician; a serious flub on his part will draw far more attention than it would have, before he made his mark as prosecutor-general.

TRUDEAU AND THE FOOT-IN-MOUTH PROBLEM

Though he heads the third party and held just 36 Commons seats at dissolution, Liberal Leader Justin Trudeau arguably has the most to lose, and possibly gain, Thursday evening, for this reason: both his principal opponents have spent the past two years arguing, in one way or another, he’s a lightweight. He can show them to be wrong, or right.

Trudeau’s youth, looks, famous pedigree, and unaccented fluency in French and English made him a leadership prospect. His defeat of Sen. Patrick Brazeau in the boxing ring in March 2012 gave him street cred as someone who could take a punch and dish one out. This debate Thursday is the first real opportunity Canadians will have to see whether any of that translates into political gravitas. If Trudeau, already slipping in the polls, appears weak, he will cement the emerging narrative he is a fallen star. And if he messes up in a serious way, he may do himself and his party in.

If, on the other hand, the Liberal leader gives as good or better than he gets, remains poised in the face of attacks and appears strong on his feet, he may emerge the big victor, for having entered as the underdog.

What makes this different even from the 2011 federal TV debates? Simply, the overwhelming prevalence of social media. Every moment of this encounter will live forever online.

Mistakes will be clipped and spooled. Thursday night Harper, Mulcair, Trudeau and Green Party Leader Elizabeth May become high-wire artists working without a net. For that alone they deserve our sympathy, as much as our attention.