The provincial election campaign in Ontario hits full stride Wednesday, as the three main parties begin airing ads designed to sway voters who take to the polls Oct. 2.

Following the strategy that proved so effective in the 1999 election, the governing Progressive Conservative Party's spots take aim at Liberal Leader Dalton McGuinty, portraying him as a tax-happy union lackey.

"He's still not up to the job," a voice says in one spot as a question mark fills the screen above an unflattering head shot of the Liberal.

John Wright of Ipsos-Reid told Canada AM Wednesday that political campaigning has gone on the attack throughout recorded history.

"Archaeologists in Pompeii found scrolls that said 'if you're not in favour of killing lions, you're a lion lover'," Wright said.

They've endured because they can serve as a sharp political weapon.

"This is not meant to appeal to everybody," Wright said. "You're looking at a narrowcasting band almost like selling a product -- to try to convince a group of people to either get out and vote, or, change where they are today."

But the strategy can backfire.

"If there's an embarrassment about them, or the veracity of the claim is challenged by a lot of people, then people may not be as encouraged to put signs out on the lawn," Wright said.

Breaking with past practice, the Liberals kept their ads secret ahead of their broadcast for "strategic reasons."

The first Liberal ad aired Wednesday featured McGuinty delivering a message focused on policy, straight to the camera.

"I won't raise your taxes, but I won't cut them either. Our schools and hospitals need that money desperately. That's our priority. That's our focus," McGuinty says, urging voters to "choose the high road."

Ontario Liberal Party president Greg Sorbara told CFTO News Wednesday, his party's strategy is to stick to leadership issues.

"We are leaving the negative to Ernie Eves," Sorbara said. "We feel the people of Ontario are sick to death of that kind of campaigning and the difference here is you see a leader who truly believes in where we need to go."

Taking another tack, New Democrat ads focus on the party's promise to keep Ontario's electricity in public hands, while criticizing the Tory agenda of privatization and deregulation.

"The blackout makes it obvious," Hampton says. "Privatization costs more and isn't reliable. That's what this election is all about: protecting and properly funding our essential public services."

The NDP message is a safe one, according to Wright.

"It's going to keep their core," Wright said. "But right now I think they're going to be contained at about 15 per cent."

As the campaign develops, the parties are expected to try different approaches. But they will be wary of overstepping the public's limits -- and especially careful not to duplicate the effect a federal Conservative attack ad had on Jean Chretien in 1993.

The ad focused on Chretien's physical appearance.

"In fact, that ad cost the Conservative party basically the party across the country and the chance to form a government in the foreseeable future," Wright said.

With files from CTV News and The Canadian Press