* The fact that the Greens have an MP in parliament
* The precedent set in 1993 when the Bloc and Reform were allowed into debates
* The fact that the Greens are fielding candidates in almost every riding
* The results of recent by-elections (in which the Greens bested major parties in some ridings)
* The support for the Green Party in the last election
* The solid standing of the Greens in the polls
Long time readers of this blog will know that I don't think much of the Green Party. Their over-emphasis on a platform of killing progressive taxation is wrong for several reasons: it is an absolutely awful idea; it is a waste of time because it is not going to happen; and it distracts from more productive and interesting conversation about the environment. However, I think the Conservatives' platform sucks even more and yet I support their right to fair participation in the democratic process.
As Chantal Hebert points out, the only reason the Greens can be excluded is that they don't have a narrow geographic base that can rise up in effective protest, as the Bloc and Reform had. The fact that the Greens are represented across the country is, paradoxically, what makes them weaker. They will be excluded - and the fairness of the election will be compromised - unless people of all parties insist that they be there.
I'm specifically not saying which parties chose to exclude the Greens because this shouldn't be a partisan issue. It's about fair elections.
But the cherry on top would be that Elizabeth May, whatever her policies, is a superstar speaker who would add eloquence and insight to the proceeding. She's also fully bilingual.