Splitting the vote is a major issue in fptp voting systems (US, UK and Canadian are all fptp) because it virtually guarantees the opposition will win.

This is especially a problem in Canada because it uses constituencies. Example:

If we have Party A on 40% and Party B on 60%, B wins the election.

But if B splits into B and C, if C takes anything more than 20% of the vote, A wins the election. (A: 40, B: 30, C: 20). Even though more people are probably aligned with party B, due to the split A wins.

Spread this across most constituencies then any region where B doesn’t comfortably lead will probably be lost to party A.

The knock on effect of this is that A will win by a landslide.

I do not think liberals are worried about a conservative party splitting (they would be delighted)... they wouldn’t want it to happen to themselves.

This would not be an issue with a proportional system, where the split would not reduce the percentage of delegates overall. One of the many reasons to support electoral reform!

In 1912, the US Dems got Teddy Roosevelt to run on a third party ticket for President--which took the votes away from President Taft and allowed Woodrow Wilson to win the election. Wilson "helped" give us the Federal Reserve, the IRS, and WWI. His primary advisor was Edward Mandel House--a tool of the European Bankers. Wilson was compromised and blackmailed by the same rich man who loaned him the money to pay the blackmail--Samuel Untermeyer.

But intentional "splitting the vote" has probably been around for millenia.

This might be a start- [en.m.wikipedia.org]