Imagine you support one of the three main parties and would like to vote for that party. In your riding, one candidate has been chosen to run for that party. Maybe you like that candidate and maybe you don’t like them that much, but that’s your only choice. So you go ahead and vote for the candidate that represents your party of choice.
Now it’s time to count the votes. Say your party of choice does not win. So you are now represented by an MLA for a party you did not choose. That means that you and your riding are providing support in the form of a seat in the legislature to a party that you do not want to support. It also means that you and your riding are not represented in the caucus of your preferred party.
Now imagine we had a proportional voting system. Although there are a number of voting systems that are proportional, they usually provide voters with the opportunity to have a say over candidate selection beyond the single nominated candidate that we’re familiar with. More importantly, when the votes are counted, it’s done in such a way that the overall seats in each region match up with the party vote count.
A voting system like this would create a different dynamic for voters. Instead of the pressure that many voters feel to “vote for a party that can win”, voters would truly be able to vote for the party they prefer. The result would be greater levels of support for more parties. It’s likely that the Greens would achieve higher levels of support than they currently do in the election, and it’s possible that other parties like the Conservatives would as well. It would also be much less likely for any party to win a number of seats that was much different from its actual level of support. So in the 2013 election, the 44% of the vote that the Liberals received would have translated into roughly 44% of the seats as opposed to the 58% they won with the current voting system.