[eru]

> In the primary people with broadly similar platforms run against each other. The "third parties" are factions within the two major ones.

No, you still have that problem of splitting the vote in the primaries.

Remember how Donald Trump used to be the most hated Republican candidates within the Republicans in around 2015 / 2016? As in the one that the most people actively disliked in polls; but he was different enough from the other candidates that he didn't suffer from the internal vote splitting that they did.

The primaries still use first-past-the-post in the US, don't they?