Voters are a fickle, shallow bunch sometimes. The least little thing can put them off. Nixon's sweaty lip during his televised debate with Kennedy. Stephane Dion's sad sack shrug. Stockwell Day's jet-ski ride to political oblivion.

Political history is littered with the corpses of promising careers brought low by such seemingly trivial incidents. Oddly, they often seem to involve sports.

In 1974, Conservative candidate Robert Stanfield was photographed tossing a football around during a campaign rest stop in North Bay. While he caught the ball perfectly most of the time, it was the shot of his one awkward fumble that hit the front page of the papers the next morning. It gave Canadians an image of Stanfield as clumsy and inept, and is generally acknowledged to have cost him the election.

Far less common are the serendipitous moments that transform the public image of a candidate or a party for the better. I can think of two offhand. One was George W. Bush's brief moment of heroism-by-proxy as he stood wielding a bullhorn amid the ruins of the World Trade Centre, in solidarity with the first responders who he would later betray.

Another was when newly crowned Liberal leader Pierre Elliott Trudeau, regarded at the time as a charming but effete intellectual, attended the St. Jean Baptiste Day Parade in Montreal the day before the 1968 election. Separatists started throwing rocks and bottles at the reviewing stand but Trudeau refused to budge, even after the other dignitaries fled. The footage was broadcast across the country, and Trudeau was suddenly perceived as not just charismatic but tough and fearless.

He won by a landslide.

We may have witnessed one of these rare moments on Saturday night, when Liberal heir apparent Justin Trudeau took on a trash-talking bruiser of a Conservative Senator in the boxing ring and, against all expectations, beat him soundly.

As a purely physical contest, the outcome really shouldn't have been as much of a surprise as it was. Brazeau may have looked like a beast from some UFC cage match, but by the time Trudeau had finished putting an extra 20 pounds on his lean frame the two men weighed in within a few pounds of each other. Brazeau might have had a black belt in karate, but that clearly couldn't help him against Trudeau's 20 years of boxing experience. Add to that the taller man's longer reach, and Trudeau's victory wasn't really all that remarkable.

As a political metaphor, it's a whole other story. Because really, who expects the Liberals to win at anything anymore?

Certainly Trudeau's own party didn't want to draw attention to the event, lest it turn into one more humiliating defeat. And it might have passed virtually unnoticed if the Conservatives themselves -- and their media surrogates at SunTV -- hadn't been so vocally and gleefully anticipating the beat-down of the son of their most hated political rival. They were the ones who invested the whole thing with profound symbolic and political importance, even to the extent of using it as a taunting non sequitor during Question Period.

If Trudeau had lost, we would never have heard the end of it. Like Dion's shrug, the image of Brazeau's glove smashing into that patrician Trudeau nose might even have inspired its own website. PunchTrudeauintheFace.ca perhaps?

Instead, we are left with a very different image. A positive image, which isn't nearly as easy to bottle and sell as a negative one. Nobody really cares enough about Patrick Brazeau to gloat over his defeat, and it would be a little ridiculous to try to deliberately craft a political narrative around the victory of brains over brawn, of quiet grace over braggadocio, of strength of character over mere muscle, of...

Ugh. See how easy it is to get carried away? Still, there's a reason why there are so many sports movies out there, and why so many of them are about boxing. Any good screenwriter will tell you, it's never really just a game, or just a fight.

If the Liberals are smart, they won't even try to manipulate this. They'll just let the image of Trudeau wiping the smirk off Brazeau's bleeding face sink in and work its magic. Images are insidious, and just like Dion's shrug or Stanfield's fumble, this one could slowly infect the national subconscious and, with any luck, subtly shift how Canadians perceive both the party and its young champion.

The biggest effect of all this might just be on the Liberals themselves. They've gotten used to thinking of themselves as losers, so nobody was more surprised than they to see Justin Trudeau triumph against such an adversary.  Somehow this unlikely victory has given Liberals a chance to do something they haven't done in a very long time.

They've started thinking of themselves as winners again. And that might make all the difference in the world.