[specialist]

The root cause is Duverger's Law https://en.wikipedia.org/wiki/Duverger%27s_law

TL;DR: With FPTP, each belligerent tries to form the smallest winning coalition, resulting in a near even split two-party system.

Proportional Representation is the remedy for assemblies, councils, houses.

Approval voting is the remedy for executive races (eg sheriff, mayor, governor).

Additional benefits of both PR and Approval Voting:

- no more primaries

- fewer elections means reduced voter fatigue

- increased turnout, because real competition boosts participation

- greatly reduces mudslinging, because everyone wants to be your second choice

- no more spoilers, making an incubator for third parties

[squiggleblaz]

Duverger's law isn't the whole picture. Normal FPTP assemblies the size of America's have third parties (see Canada, UK, India).

Some PR countries have strong two party systems (see most obviously Malta).

There is something additional in America that causes a two party system which may or may not continue past a switch to PR because we don't know what it is.

Also, it is good to specify your goals. You might want to make it easier for unconnected people to enter the assembly, or to make it easier to throw out the choice of the primary voters, or literally just a more fragmented assembly. It is easier to come up with useful compromises if you specify your specific objectives because not every system of PR will have any of those goals. Closed list PR with primaries is probably the antithesis of what you want, but it's an extremely common kind and what a lot of people hear when you say "PR".

[specialist]

I've mostly studied USA elections and legislatures. So am ill-equipped to compare, contrast. But being very political, and having run for office and done some policy work, I can comment on our elections.

Over simplistically:

#1 - Our FPTP elections leads to two major parties.

#2 - Our gerrymandered districts (local, state, congressional) has led to increased partisanship. As noted elsewhere, because contests are won during the low-turnout primaries where the motivated base participates.

#3 - Ever increasing campaign costs has led to concentrated influence (power law distribution of attention). Who ever controls the contributions controls the agenda.

#4 - We have city, district, county, state, federal elections. The party system starts at the bottom. Memories are long and defections are never forgiven (eg Nader & Green Party).

Having now done it... Everyone should run for office, at least once. Because most commentary, complaining isn't even wrong.

My goal, always, is to empower, enfranchise people. The various reforms I support increase voter choice and participation. At every level by various (sometimes non-intuitive) means.

[ClayShentrup]

While there are a few minor examples of Plurality Voting countries escaping duoploy, they are by far the exception. America's duopoly seems clearly a result of using it.

I wrote something about this. https://asitoughttobe.com/2010/07/18/score-voting/

[jessriedel]

Proportional representation just shifts the coalition building from the electorate level to the legislative level. It's well known that such coalitions tend to be the smallest majority possible.

You may think for various reasons that it's better to form coalitions at one level of the voting process than the other, but let's not pretend PR avoids it.

[int_19h]

The difference is that legislative coalitions don't have to be permanent, the way parties are. Various factions in the legislature can come together for a particular bill, or series of bills on some issue that's relevant to them all. But on something else, they might realign differently. Also, even when coalitions are more persistent, the terms are effectively renegotiated every election - party platforms are much more stable.

[squiggleblaz]

American parties aren't exactly permanent tho are they? How many bills have fallen this year because some republican senator wouldn't support it? And I certainly wouldn't describe Trump's Republican administration as pursuing the same platform as Bush II's. Certainly there's similarity but not the stability you imply.

[int_19h]

I didn't say that they are permanent. But they change very slowly. More importantly, they mostly change by accrual; you rarely see old polices dropped hastily. Indeed, even for all the Trump rhetoric, the current administration (and legislature) is not doing anything that wouldn't be expected from a Republican government.

The reason why we have so many bills falling through is because of the razor thin margins in the Senate, so that a few dissenters can affect things. But if you look at how votes in legislature went down historically, we're pretty much at peak partisanship - it used to be a lot more common for congressmen to vote across party lines.

[jessriedel]

You're failing to draw the correct analogy in each case.

> The difference is that legislative coalitions don't have to be permanent, the way parties are.

Just like the parties that make up a legislative coalitions can change, the voters making up a political party can and do change.

> Various factions in the legislature can come together for a particular bill, or series of bills on some issue that's relevant to them all. But on something else, they might realign differently

This happens all the time on individual bills in a two-party systems as well. ("Crossing the aisle".) But the coalitions forming control of the legislative body rarely change except immediately following elections (in both PR and two-party systems).

> Also, even when coalitions are more persistent, the terms are effectively renegotiated every election - party platforms are much more stable.

The analog of a particular legislative coalitions in a two-party system is not a particular party but the party in power. And the platform of the party in power changes dramatically when power shifts from one party to another.

[specialist]

Former US Rep Henry Waxman explains in his book The Waxman Report how Congress used to work, where coalitions were often formed around issues, interests.

There are many other accounts, giving different perspectives, of course. The Politics of Attention and Unorthodox Lawmaking come to mind.

[lambertsimnel]

Among the many disadvantages of taking coalition building away from the legislative level (where it is in most democracies) is that it no longer takes more votes to win than to lose. With single-winner districts, a party getting more votes and fewer seats than another party and a majority government can rule with a minority of the votes.

[ClayShentrup]

PR mostly nullifies Gerrymandering.