I'm not sure it's a deeper structural issue. The issue is actually pretty simple; first-past-the-post voting. This automatically leads to a two-party system.
Canada currently has 338 MPs and over 80% (!) of those (278) belong to one of two majority parties.
So yes, in theory Canada has a multi party system. In practice this multi party system is severely damaged by the effects of the FPTP voting system.
There are mathematical reasons for FPTP to result in two party systems. [0] explains it pretty well. There don't have to be deeper underlying stuctural reasons for the dichotomy.
So to combat two party systems, replacing FPTP with an alternative voting system seems a pretty reasonable step.
Which is also true of Australia which has had instant runoff voting for nearly a century.
I would suggest you look at the actual examples in the wild, and see if they have FPTP (or party proportional representation, which is essentially FPTP with all the same spoiler effects), and which don't, and see if they match your expectations to any degree better than random chance.
You can prove just about anything in "math" in a vacuum. The recent push for FPTP really strikes me as the kind of wonk stuff that people bend themselves around as a huge fix, when the reality is it empirically doesn't do what people thinks it should do, and comes with it's own problems. It's a lot of wasted political capital for very little if no benefit.
No, not really. If you look at Australia's parliament, you'll see that even though Labor and Liberal are the biggest party, they 'only' make up 60% of the seats. That's not really good, but it's a far cry from Canada's 82% (or the US's 99%)
> I would suggest you look at the actual examples in the wild
That's a very good suggestion. I actually already did that and I can assure you not using FPTP results in much more and smaller parties.
Examples:
- Ireland (STV)
- Northern Ireland Assembly (STV)
- Papua New Guinea (IRV)
> The recent push for FPTP
Do you mean 'against FPTP'? Because I can assure you that I'm not pushing for FPTP at all.
> No, not really. If you look at Australia's parliament, you'll see that even though Labor and Liberal are the biggest party, they 'only' make up 60% of the seats. That's not really good, but it's a far cry from Canada's 82% (or the US's 99%)
I'm not sure how you came to that. Australia has 151 MPs, 68 in the liberal party, and 61 in labor, or 86% in the two major parties. Their senate has 76 members, 31 liberal, 26 labor, or exactly 75% in the two major parties.
> Do you mean 'against FPTP'? Because I can assure you that I'm not pushing for FPTP at all.
Yes, I misspoke there, as is clear from the rest of my argument.