Ontario NDP Leader Andrea Horwath spent the first official day of campaigning making it clear who she considers her biggest adversary, focusing her criticism squarely on the Liberal Party.

Barely even mentioning PC Leader Tim Hudak's name, Ms. Horwath gave speeches and mainstreeted across Southwestern Ontario Wednesday in areas where the NDP has found success before, and hopes to expand its grasp. Calling the Liberal Party "cynical" and saying she didn't trust "a single thing the Liberals say," Ms. Horwath laid the groundwork for her yet-to-be-revealed platform by taking aim at the Grits' plans.

"The Liberals make lots of promises, but they never deliver," Ms. Horwath told a handful of supporters, standing in front of Niagara Falls Wednesday afternoon. She specifically called out the government's decision to end the Slots at Racetracks program, which meant the nearby Fort Erie track was excluded from a new funding partnership.

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"The plan was a back-of-the-napkin plan that disrespected Fort Erie as well as a number of other small racetracks around this province."

The NDP's campaign strategy, party insiders confide, hinges on attracting Liberal supporters disaffected by years of spending scandals.

One senior NDP source said, however, that the party believes that even though these voters want to punish the Grits, they don't want to condemn them completely – hence Ms. Horwath's relatively mild declaration the Liberals need a "time out." The NDP, in effect, is walking a fine line, trying to get Liberal supporters to turn away from leader Kathleen Wynne without turning them off of Ms. Horwath by being overly negative.

The Liberals, meanwhile, are more afraid of the NDP than they are of the Tories. The party's research, sources say, shows they are primarily competing for votes with Ms. Horwath, while few Tory supporters would ever consider voting for anyone else.

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Ms. Wynne has regularly criticized her NDP counterpart for "having no plan" on everything from pensions to transit in her stump speeches through the opening days of the campaign.

But Ms. Horwath countered the attacks by saying her party does have a plan, it's just not ready to show all its cards yet. Instead, they're trickling out their platform points a little at a time.

The election was spurred last week when the NDP announced it would not be supporting the Liberal budget.