There is one aspect of the
While giving voice to regional majorities (which are minorities relative to the entire nation), the plurality system disfavors minority parties nationwide, resulting in a two-party system (with the
Both are extremes and, as in many other cases, two opposites merge. A multi-party system is the extreme of radical democracy bordering on anarchy. When everyone rules, no one in particular rules, and the other way around. In a radical democracy, no one's life, liberty or property is secure, since it is driven by the spur of the moment and by the whims of anyone who happens to be in power. This system tends to either clamp down on individual rights whenever a radical coalition comes to power or neglect the protection of rights while it's busy with factional infighting (this is why some of the Founding Fathers criticized political parties). A dominant-party system, on the other hand, is the rigid despotism of a minority. Since both are types of arbitrary government, they often turn into each other.
A two-party system is the golden mean. It promotes moderation (moderation is not always good but in this case it is) and is hostile to radical activists seeking to undermine the constitutional system. One could argue that it is also inconvenient for libertarian activists but the point is that they would be unlikely to usher in a libertarian society if they are a radical minority in a hostile nation (misunderstood by everyone, their ideas would be discredited).
Another aspect of