It's not conservative parties that benefit. Any party that benefits from squeezing out smaller 3rd parties and giving them a 50/50 chance at power (per
Duverger's law) is a benefactor. Federally, the CPC benefits by the strength of the NDP and have reason to maintain a multi-party system in times when tactical voting collapses. But provincially, it's almost universally a de facto 2-party system thanks to unassailable tactical voting (Ontario, Quebec and maybe Nova Scotia being the exceptions), with the Liberals or NDP being the progressive-vote benefactor. And to the surprise of no one, the provincial NDP are just as obstructive of electoral reform as a conservative party is, in full contradiction of the policy of their supposedly-unified party.
Alberta had 3 parties and they just downsized, while BC's Green Party has finally grown to a point that it can achieve less than 3 seats with highly-targeted campaigning but are hardly expected to make further gains and is the only reason that Horgan likely changed his tune on electoral reform.
So we can't look at this as purely a conservative-only effort to undermine attempts at electoral reform. It's any party that benefits from Duverger's law.
