What's a bit shady about all of this is the process by which we decide who gets to participate in the debate and who does not. Given that there are nineteen official political parties in Canada, it isn't feasible for all nineteen leaders to debate each other. Being included is obviously a sign of a particular status in the party system, above and beyond meeting the criteria for party registration in the Elections Act.
Some criteria have to be used to decide who gets to participate and who does not. The issue is that there are no clear rules on this and the decision is controlled by an equally nebulous "broadcast consortium" (a coalition of sorts) of the five major Canadian television broadcasters. There is no clear explanation as to why they invite some leaders and exclude others.
I personally believe that Elizabeth May should be invited to join the debates -- her party runs 308 candidates, meets the vote threshold for both the quarterly allowance and the election expenses reimbursement, and her party was the only one that saw its absolute number of votes increase between 2006 and 2008. Frankly, I have a much harder time seeing the point of Gilles Duceppe's participation in the English debate. But the larger point is that the rules aren't clear and it isn't clear who makes those rules.
It's time to take this out of the hands of broadcasters. Our neighbours to the south have a pretty good model: The Commission on Presidential Debates. They have established clear rules -- like them or not -- over what qualifies a party's leader to participate in the debate. Perhaps the campaign could move beyond arguing over who should be included in the debate and actually focus on what the leaders say during those debates.