[1] Multi-party systems tend to be more common in countries using proportional representation compared to those using winner-take-all elections, a result known as Duverger's law.
In these countries, usually no single party has a parliamentary majority by itself (hung parliaments).
Instead, multiple political parties must negotiate to form a coalition with a majority of the vote, in order to make substantial changes.
Some theories argue that this allows centrists to gain control, though this is disputed.
[2][3] Argentina, Armenia, Belgium, Brazil, Canada, Denmark, Finland, France, Germany, Iceland, India, Indonesia, Ireland, Israel, the Netherlands, New Zealand, Norway, the Philippines, Poland, Sweden, Tunisia, Turkey and Ukraine are examples of countries with multi-party systems.