A non-American asked in a Redddit thread recently in regards to national American elections “Wouldn’t it be easier to just switch to proportional representation”. Below are my responses, in part, outlining why this is not only the opposite of “easy” but an unwise decision overall.
It would be the opposite of easy since it would require an upheaval of the entire Federal Constitutional arrangement. Such a scheme would require a national election, and in the United States we don’t have a national elections, but 50 individual state elections each generally run their own way, and changing that would strip them of their power and centralize it in the hands of a single massive government.
The downside of doing this is that with the current system, any voter suppression or election fraud in one state does not and can not affect the outcome of races in other states including races for Senator, Representatives, or for President (Electors therefor, specifically).
Moving to proportional representation would actually reduce political diversity and make the system less democratic. While there are two major parties in the U.S., they are themselves more akin to broad coalitions in reality and politically quite diverse (though not as much as they used to be); additionally, the 50 state (+6 territory/DC) parties are autonomous and generally run their own affairs which prevents concentration of power. Additionally, unlike many if not most countries, in the U.S. party nominees are usually chosen by the voters of that party directly; not only does this mean that you can have many different and even contrary voices within each major party, but that it also preserves local control and influence, which again helps counter centralization of power by protecting the voices and interests of different communities.
People don’t vote for political parties (though some state’s allow you to vote for candidates of the same party all at once on a party-line ticket). People vote for individuals, and those elected officials are far more dependent on the favor of the electorate than they are with party leadership to the point where party leaders have effectively little to no choice in many primary elections where the people directly nominate their preferred candidate.