The U.S. stands out among the former British dominions that share Britain's electoral system, commonly known as 'first past the post' or 'winner take all.' The U.S. version is called single-member plurality system.
This system does not provide effective representation to minority views or people that are more or less evenly distributed across the country and as Duverger's law suggests, it ends up in a 2-party system. Especially when socialist movement is weak unlike other former British colonies such as Canada and India, the parties turn into big tents of quite divergent, even conflicting ideologies. As a result, what goes as social democrat in Europe, goes as liberal in the U.S. Even further, with the absence of alternatives, minority views and people, such as African-Americans do not have leverage as they would have in a multi-party system, where more than just Democratic Party would have tried to represent their interests, and this would have created competition among parties to get their votes.
In your opinion, should do U.S. change the electoral system to Proportional Representation for better representation and a more balanced national politics where different ideologies and positions can be represented under new parties instead of being locked into only two parties? What would be the effects on the Presidency if the U.S. had more than 2 parties both during election time and during different presidential administrations?