This proposal on the upcoming federal election talks about some interesting gaming of the voting system.

In Canada, there are 3 (and sometimes more) strong parties. This is true in much of the world; in fact the two-party USA is somewhat unusual. However, with "plurality" style elections, where the candidate with the most votes takes the seat even though they might have well under a majority, you can get a serious difference between the popular vote and the composition of the house. Americans see the same in their Electoral college and in gerrymandered districts.

The author, who wishes to defeat the incumbent Conservative party, proposes a way for the other two parties (Liberals and New Democrats) to join forces and avoid vote splitting. The Liberals and NDP are competitors, but have much more affinity for one another than they do for the Conservatives. They are both left-of-centre. This collaboration could be done at a national party level or at the grass roots level, though it would be much harder there.

Often in parliaments, you not only get splitting within the race for each seat, you get a house where no party has a majority. For minority governments, one party -- usually the largest -- strikes a deal with another party for a coalition that allows them to govern. Sometimes the coalition involves bitter enemies. They cooperate because the small party gets some concessions, and some of their agenda is passed into law, even though far more of the dominant party's agenda gets passed. Otherwise, the small party knows it will get nothing.

The proposal suggests two parties should collaborate before the election, rather than after. It identifies 16 ridings (what in the US would be called districts) where the Conservatives have a slim lead over one of the left parties, and the other left party is well behind. The argument can be made that, even with the unreliability of polls, it's very clear that the 3rd place candidate is not taking that seat. They propose that this 3rd place candidate publicly throw support to the other left candidate. (It's too late to physically withdraw.) If done, this would work, and 8 candidates from each left party would be elected instead of 16 Conservatives, and that should indeed swing the election if other polls are right.

On the surface, that seems very rational. Polls are notoriously wrong, particularly in parliamentary elections, but they are getting better and there is a limit to their error. Candidates can indeed know they are not going to win, and they are fighting just on principle. They can know that by fighting, they will split the vote and give the riding to the Conservative. Again, the NDP and Liberals are far from tight bedfellows, but they both see the Conservatives as their main opposition.

Even in spite of the numbers, this can still be a lot to ask somebody who has put so much into fighting a race. They would be asked to "take one for the team."

For the parties, the rationality is much more clear. The main negative would be that some would see this as cheating, though it is the norm in all leadership conferences to have the winner decided by losers who throw their support when they can no longer survive. There is also the slight risk that serious poll errors could result in a candidate withdrawing who later is revealed to have had a chance.

The parties could go further. With the chance to be the government, they could offer perks and rewards to the candidates who withdraw to take one for the team. All the way up to safe seats in future elections, or seats in the Senate, though it would be hard to reward all them that way. They would need to be stars in the rough -- you don't offer perks like that to people who are losing for a reason.

What all of this would do is reduce vote splitting. The real way to do that is to switch to some sort of multi-candidate election. That's an election where instead of just picking one candidate on the ballot, you can name 2 or more, and possibly rank them in order. In Australia, this is how elections are done. The ordered ballots allow the lowest candidate to be eliminated and an instant runoff done with their votes distributed to their supporter's second choices, and so on until you have only 2.

The Australian STV system is well tested, but it has a number of flaws and confuses voters a lot. Today, many election theorists like some other systems. The Condorcet method is good if you have a rank ordering, though it sometimes generates 3-way ties. I have come to favour the vastly simpler Approval voting system, where you can simply vote for as many candidates as you like -- with no ranking. It has some slight strategy to it (unlike the ranked ones) but is super easy to understand and use, which turns out to be important. The public has to understand the system and have faith in it.

Why don't we use these systems today

Some countries do use them, but most don't. One reason it's hard to switch is that there are always powerful entities who would suffer if a switch were made to the counting system. That's true for any switch -- in fact, we would not seek a switch if it would have no effect. Not only that, most parties can see that while sometimes the new system would help them, in other times it would hurt them. They don't like the risk.

If changes require constitutional amendment -- and in many countries, they do -- it becomes almost impossible to pass something that has super strong opposition from powerful parties. In the USA, it's clear that such systems would have altered the 2000 Florida results strongly for Gore, but they would also possibly have altered the 1992 election over from Clinton to GHW Bush with the Ross Perot factor eliminated. Neither party is going to get strong support behind that trade-off, and as such it is hard to make it happen.

In Canada, a change to federal election rules might be possible just in the Elections Act, not in the constitution. So if a coalition that was very strong decided to gain power with this trick, and then put it into the law, it's not out of the question.

Politics, however, is about people sometimes even more than principle. Asking people to step down like this is a pretty big step. So I doubt it will happen.