The LPC campaigned on 2015 being the last election under FPP, along with ensuring "every vote counts".

When you say "make every vote count" this necessarily means proportional representation (PR). PR is the only viable long term solution being pushed by electoral reform advocates. Some examples of PR electoral systems:

• Mixed member proportional (MMP)
• Single transferable vote (STV)

Trudeau has only ever (secretly) wanted instant runoff voting (IRV) to replace the current first past the post (FPP). So when the tide shifted against him, he broke his election promise and bailed on electoral reform.

In either IRV or FPP, many votes will not count at all (>=50%). So neither IRV nor FPP satisfy the criteria for proportional representation (PR).

Note: lots of people use the term "ranked ballot", but this is inaccurate. Ranked ballot is simply a mechanism, and not an electoral system. For example, both IRV and STV use the ranking mechanism, but only STV is considered PR.

So while Trudeau was pushing for "ranked ballot", along with the "make every vote count" messaging, people are right to infer that STV would be implemented. STV uses ranked ballot but is still considered PR.

So that's 4 electoral systems:

1. First-past-the-post (FPP)
2. Instant-runoff voting (IRV)
3. Mixed member proportional (MMP)
4. Single transferable vote (STV)

Only MMP and STV are considered PR!