Parliamentary systems allow for numerous parties and the leader of the party gaining the most seats in parliament becomes the national leader...this works well in many countries..as for monarchies..those that work well understand something that republics, especially America, dosen't..it is always a good idea, in a democracy, to separate power from glory. I think countries , especially democratic ones, adapt systems that suit their cultural needs. A look at America would seem to suggest that a third party might be a very good idea.