What we will really see is probably the following:

- Sometime in the late summer/early fall Justin Trudeau will prorogue Parliament.  It is fairly normal to do this about halfway through a 4-year term.
- Once the new session starts the Liberals will lay out a (very?) rough outline of a plan to change the electoral system AFTER the 2019 election... should they win
- Some more study might be done and maybe some more paperwork but no real change will be implemented prior to 2019
- For the 2019 election the Liberals will, once again, promise that it will be the last election held under the 'first past the post' system
- Rinse, wash, repeat