I’ve had some ideas, but I am the first to admit they are no well hashed out and my political science knowledge is sorely lacking. However, this is more or less how I thought about the traditional American political system and its nice to have some back-up from Matt.
Historically, the United States has been dominated by an ideology of non-partisanship driven by precisely the suspicion that the interests of a party or faction are not those of the country. And for most of America’s history, when parties were largely non-ideological, this made a ton of sense. A non-ideological party, after all, is basically just an interlocking web of patronage networks and party machines. If a Democrat is in the White House, then Tammany Hall gets to reward its supporters by handing out federal jobs in New York City. The machine couldn’t care less what the president thinks about “the issues” (unless the issue is civil service reform) it just wants a president who recognizes his affiliation with the machine.
This is suggests that side payments or patronage was a key part of making the American political system function. If you look at it through my lense this makes sense. If you can milk the political system for profit it no longer becomes a zero sum game between incumbent participants.
Everyone who is in power has a strong interest in maintaining the existing power structure because it provides profit for them both. That is you are a Democrat and I am a Republican but we are both milking the same cow, so we might as well get along.
When cow milking no longer becomes acceptable then we are pure enemies locked in a zero sum battle. Hence, an inevitable descent into constant warfare.