Lending excitement to a normally slow season, five Ontario by-elections set for Aug. 1 are getting lots of hype. As ever, there are dangers in reading too much into such votes. But while they may not be accurate predictors of what will happen in the next general election, and won't affect the balance of power in the minority legislature before then, there are plenty of reasons why this summer's campaigns matter.

They'll either end or extend Kathleen Wynne's honeymoon.

The rookie Premier has had a pretty good first few months – avoiding an election, improving her Liberals' poll numbers and getting positive coverage. But even though by-elections largely come down to local candidates and organization, they'll still represent Ms. Wynne's first real test with voters since taking the helm.

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Although the Liberals have little hope of retaining the Windsor riding long held by former finance minister Dwight Duncan, keeping the other four erstwhile Liberal seats up for grabs would give Ms. Wynne her best claim yet to having restored her party's fortunes after Dalton McGuinty went out ugly.

If the Liberals can keep three of the five, it might be a wash. Any fewer, and some of that lustre will wear off.

They'll either ease Tim Hudak's troubles or add to them.

Facing a chance of getting shut out in all five ridings, the Progressive Conservative Leader – wary of giving fodder to his many critics – tried to lower expectations. But then he recruited Doug Holyday to run in Etobicoke-Lakeshore.

Toronto's deputy mayor is a great catch, and if he can win a high-profile battle with fellow councillor Peter Milczyn, he'll establish a Tory beachhead. If the PCs could also win a three-way battle for the London West seat vacated by former energy minister Chris Bentley, or pull off an upset in Mr. McGuinty's old Ottawa South riding, it would help get Mr. Hudak's critics off his back.

The gambit with Mr. Holyday, though, has raised the stakes. If even he can't get elected for the Tories, it will lead to some more finger-pointing.

They'll provide much-needed bench strength.

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Ms. Wynne's front benches are not brimming with big personalities. While it's unlikely they would be placed in cabinet immediately, the likes of Mr. Milczyn or Mitzie Hunter – the CivicAction CEO running in Scarborough-Guildwood – could ultimately play high-profile roles. The same might be said of former teachers' union head Ken Coran, running in London, if he's not too polarizing.

As a potential senior minister, Mr. Holyday alone would help the Tories present themselves as a government in waiting.

While the NDP's caucus has improved under Andrea Horwath's leadership, it's still a work in progress. Percy Hatfield, a city councillor and former CBC personality running in Windsor, stands to give it another relatively strong voice. So, too, might former school board chair Peggy Sattler if she can win in London.

They could establish new strongholds.

With a good chance of the next general election producing another minority government, every seat counts. And incumbency, even established under the unusual circumstances of a by-election, can be a huge advantage.

For the Liberals, the worry has to be about losing that advantage. Ms. Wynne's party still harbours hopes of winning back majority government. It was wiped out of most of rural Ontario, so its electoral map will not make that easy. If it loses its grip on a riding such as London West or Ottawa South, in addition to its likely loss in Windsor, that map will get all the more challenging.

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The opposition parties, meanwhile, have to know that they won't get any better chances to add these particular ridings to their maps.

They'll test on-the-ground organization.

Because of their low turnouts, by-elections are largely get-out-the-vote contests, with campaign workers all but dragging supporters to polling stations. But that's an increasingly important part of general elections as well, so the parties may relish the opportunities to take their operations for test drives.

Superior GOTV efforts have been a big part of the Liberals' success in recent campaigns. They will also enjoy a big advantage this summer because they have hundreds of staffers – far more than the opposition parties – who will be expected to do some less-than-voluntary volunteer work. Still, the races may offer some indication of whether the Liberals' organization has survived the transition from Mr. McGuinty to Ms. Wynne intact, and whether the other parties have managed to narrow the gap.