Ad Hawk is an occasional series evaluating the effectiveness of political advertising.

It's called framing. And the Conservatives are experts at it.

It's a concept political strategists borrowed from George Lakoff, a highly respected linguistics professor at the University of California, Berkeley. Simply put, a frame is the image that's embedded in the public's mind when they think of a politician. Once that frame is established using loaded language and constant repetition, it's very difficult to change.

The key is to define your frame before someone else does it for you.

Stéphane Dion was framed by the Conservatives the moment he became Liberal leader. It started with an ad on Super Bowl Sunday, 2007. Using clips from a debate with rival Michael Ignatieff during the Liberal leadership campaign, the ad showed Dion responding to Ignatieff: "This is unfair. Do you think it's easy to set priorities?" The ad's voice-over closed with: "Leaders set priorities. Leaders get things done. Stéphane Dion is not a leader." It stuck.

The Conservatives had success in the 2008 election by defining then Liberal leader Stephane Dion with attack ads. (Fred Chartrand/Canadian Press)

Ignatieff was also framed as soon as he became Liberal leader in 2009. The ads were devastating. He was "just visiting" and "not in it for you." After more than 30 years living outside Canada, he was framed as an opportunist returning for his own interests. He never recovered.

Attack ads don't always work. In some cases negative campaigns have substantial effects on voter impressions. In others, the effect is negligible. However, as a general rule, there has to be some truth in the ads to be effective. The Conservatives tapped into their opponents' weaknesses, magnified them and let their whiny responses further reinforce the frames in the public's mind.

There is no silver bullet in advertising, but this formula has worked to perfection for the Conservatives. So it was predictable that Justin Trudeau would become the target of attack ads.

The messages aimed at framing him as "just not ready" began long before the start of the official campaign, and they stuck. Forty-seven per cent of the 1,384 people surveyed by Forum Research between Aug. 30 and Sept. 1 believed Trudeau was not ready to be prime minister. Thirty-nine per cent thought he was. To put this in perspective, 47 per cent in the same survey thought the NDP's Tom Mulcair was ready for the job.

But just how solid is that frame? It proved virtually impossible for Dion and Ignatieff to shake the Conservatives' frames. But being labelled as "not ready" is not a political death sentence. It's about not being ready for prime time, yet. That's a frame that isn't carved in stone.

Take the ad that's worked the hardest at framing Trudeau as not ready, the one showing a group of interviewers assessing whether he has the experience required for the job based on his resumé. They could have rejected the application simply because, as one of the interviewers claimed, "being a prime minister is not an entry-level job." Instead, the ad left the door open. The Conservatives chose to add a line that could come back to haunt them: "I'm not saying no forever, but not now." That's a surprising concession in an attack ad.

Taking it on the chin

The Conservatives could not possibly have run a heavier media campaign accusing Trudeau of not being ready.

And they took attack ads to a new low with an online ad that used actual footage from horrific videos posted by ISIS.

But Canadians were not only watching the unavoidable ads, they were watching how Trudeau dealt with the blows. He took most of it on the chin and carried on with his message apparently unshaken. Images of the Liberal leader with boxing gloves may also have played a symbolic role to counter the perceived weaknesses of the untested leader.

The Conservative Party's 'interview' television ads claiming Justin Trudeau is 'just not ready' to be prime minister has been in high-rotation. (Conservative Party/YouTube)

The Conservatives' framing of Trudeau required that "Justin" be the name of the former camp counsellor with nice hair (a kid just like the other Justin, the pop star), not that of the next prime minister. As the public took a closer look at Trudeau, they also saw that the kid they first met in the arms of his father in the '70s was grown up and happened to be the same age as John F. Kennedy when he became U.S. president. That may explain why Harper has been calling him Mr. Trudeau more recently.

The long interview

The longest election campaign since 1872 has created the longest job interview process for the leaders in modern times. It's meant more hoops and hurdles to jump through and, in Trudeau's case, it meant more time to convince people he's ready for the job. His performance in the debates confirmed he's at least battle-ready.

It's a risky move to repeat your opponent's attacks in an ad. However, many observers agree the Liberal ads have been effective in hijacking their opponents' message. They stuck to the party's narrative even when confronting the "not ready" line, with Trudeau saying he was "not ready to watch hard-working Canadians lose jobs and fall further behind." The most recent ads are all about Canadians' readiness for change and the Liberal leader's own readiness.

After 78 gruelling days on the campaign trail, eight years in Parliament, two as party leader, the framing of Justin Trudeau as "just not ready" might still hold for many voters. But, on election day, those looking for change could decide he's no less ready than Harper was 10 years ago.

And the interviewer in the Conservative ad who said "I'm not saying no forever, just not now" may feel that this campaign has gone on long enough and Trudeau is ready to be promoted.

Eric Blais is president of Headspace Marketing, Inc., a strategic consulting firm. He specializes in the Quebec market.

Previously from Eric Blais: