TORONTO -- Premier Dalton McGuinty's bid to win the majority government he was denied last October will be decided by the voters of Kitchener-Waterloo in one of two provincial byelections Thursday that could dramatically alter Ontario's political landscape.

"I don't know of a parallel situation in Ontario's history...where one byelection could make the difference between a majority and a minority government," said Barry Kay, a political-science professor at Wilfrid Laurier University.

The governing Liberals are expected to easily win the other byelection in Vaughan, retaining the seat vacated by Greg Sorbara, the veteran cabinet minister and strategist who quit to devote more time to his other job as chair of the party's re-election campaign.

After falling just one seat short of a majority in the Oct. 6 general election, McGuinty engineered the Kitchener-Waterloo byelection by convincing veteran Progressive Conservative Elizabeth Witmer to give up the seat she'd held for 22 years to take on a $188,000-a-year job as chair of the Workplace Safety and Insurance Board.

"It's always a little bit easier when you have a majority to act on a mandate, whether you're trying to introduce a budget or move ahead with a 'Putting Students First' act," McGuinty said this week.

Voters in Kitchener-Waterloo appear to have been turned off by McGuinty's attempts to get a majority, said Kay.

"I thought that would play better than it has," he said. "I think they are disinclined to give the party a majority. It's not just a neutral factor. I think it's a negative factor."

The Progressive Conservatives said voters aren't ready to give McGuinty his majority.

"I hear this over and over again when I'm in Kitchener-Waterloo or Vaughan, people say Dalton McGuinty does not deserve a majority government. He hasn't earned it," said Opposition Leader Tim Hudak.

"I am hearing at the doors a sense of frustration that after 10 months, the government seems to have gone backwards, with a bigger deficit and more jobs lost."

The NDP said the Liberals picked a fight with teachers and recalled the legislature for an emergency session in August -- weeks before the byelections -- to distract voters from the scandal at the Ornge air ambulance service and the $190-million cost of shutting down a gas-fired generating station days before last fall's election to save Liberal seats in the Mississauga area.

"It was a very cynical ploy that people recognized for what it was, and I think voters of Kitchener-Waterloo were really disappointed that the government decided to go in that direction instead of addressing the real issues they have there," said NDP Leader Andrea Horwath.

"They do not want to reward a government that has behaved badly, that has bought seats in the last general election with the cancellation of the power plant, that has ignored precious tax dollars by allowing scandals to happen at eHealth and the Ornge air ambulance service."

The Liberals' attempt to portray themselves as strong fiscal managers willing to get tough with teachers to make sure classes began as scheduled on Sept. 4 -- which teachers' unions had always said they would -- backfired, benefiting the New Democrats in Kitchener-Waterloo.

"The teacher question was a factor, but I think it evolved in a direction that McGuinty didn't anticipate," said Kay.

Teachers angry with the Liberals and still not willing to support the Conservatives because of the Mike Harris years appear to have turned to the NDP's Catherine Fife, a former chair of the Ontario Public School Boards Association, making the byelection a true three-way race.

"In byelections, candidates matter a lot more than they do in general elections," added Kay.

Hudak said he wasn't worried a loss in Kitchener-Waterloo would weaken his grip as leader of the Progressive Conservatives.

"It was more of an Elizabeth Witmer seat than I'd say a Tory seat or a Liberal seat or NDP seat," he said. "No matter what the outcome, Friday morning is the same for me as it is today."

Byelections are traditionally an opportunity for voters to show their displeasure with governments, and the Tories too will be able to explain away an NDP upset in Kitchener-Waterloo, said Kay.

"The Liberals can claim this wasn't a Liberal riding, and the Conservatives can claim that it wasn't really about Hudak because it was Witmer's riding, and both of those comments are true," he said.

"But there was an opportunity here, and I'm sure when McGuinty opened up that position for Witmer, he wasn't thinking 'well, here's a chance for the NDP to shine."'