Coalition governments and social democracies?

[dutchdog]

Social Democracy is not a state-structure, but a political stream (an ideology). So Social Democracy is not the reason why coalition governments to exist.

Some countries have a two-party system, others have a multi-party system. In a multi-party system coalition governments are more common. Often, there the threshold for different parties to gain seats in parliament is lower, in other words: it's easier to enter parliament as party.

In some countries that have a two-party system, there's also a Social Democratic party (or Labour), so that's another example why the two things are not connected like that.