It's because of power structures. I'm American, so I'll use US history if anyone doesn't mind. When you have an established power structure, elections are pretty straightforward; two or three coalitions slugging it out, no repeat. In the US, that would be the Republican and Democratic party. However, when the power structure is struck down or altered, chaos reigns until a new power structure emerges. Here, it would be the collapse of the CoF and Unity. In American history it would be around the 1860s when the Republican Party sprang forth from the remains of the Whig Party. Then, it was a four way election. Of course, Lincoln won, won the Civil War, freed the slaves, causing the Republicans to be in office for the next 25 years; in the process creating the new Republican-Democratic power structure that exists to present day. (My interpretation, feel free to correct if wrong.) After the collapse of the CoF, if people remember, we had a chaotic 3-way election that was decided at the eleventh hour. Then Unity sprung up, creating the second power structure. Then it collapsed, and we now find ourselves in a 3-way election.