Spoiler effect

From dKosopedia

Category: Kossary

The Spoiler effect is used in political discussions to reference the effect of third parties on first past the post election systems. If a third party candidate pulls votes away from another candidate on one end of a political spectrum, it increases the chances that the candidate on the other side of the spectrum will win.

See the Wikipedia entry on "spoiler effect". This is also known as "Independence from Irrelevant Alternatives" in Arrow's theorem.