Thursday's by-elections will be less about the the local ridings, more about the bigger picture, with strategists eyeing the outcomes to see if wins can be translated to gains in a province-wide vote.
However, one observer says the true test in Thornhill and Niagara Falls, will be if Tory leader Tim Hudak can make a clean-sweep.
University of Toronto professor Nelson Wiseman says if Hudak can't, then the party may lose confidence in him leading the Progressive Conservatives to victory the next time Ontario heads to the polls.
Premier Kathleen Wynne says by-elections are their own beasts and whatever happens after polls close, she'll still be the premier of a minority government.
The Tories hope to keep the party's Thronhill seat, left vacant after Peter Shurman resigned as MPP. The Liberals trying to save their seat in Niagara Falls. MPP Kim Craitor stepped down to spend more time with his family and look after his health.
NDP leader Andrea Horwath and her party are so confident they'll take Niagara Falls from the Liberals, that she has already scheduled an appearance there on Thursday night with candidate Wayne Gates.
Hudak and Wynne's staff have not announced their appearances.
The Liberal minority government is expected to fall after this spring budget is tabled. The NDP have helped the Liberals survive since a minority was elected with former-Premier Dalton McGuinty at the helm in 2011.