taniabunke asked: Why AV (Instant Run-Off) rather than a different non-FPTP system? AV sometimes ends up with thing like the UK Labour leadership elections last year, where a candidate who got a very small proportion of the first-ranked votes ended up winning, which seems counter to the principal of electoral democracy. Wouldn't some version of PR (or perhaps a PR and FPTP system as in Germany or Scotland) be better?

Since we’ll never abandon the Constitutional system barring some disaster, PR won’t work. We have single member plurality district elections, and PR can’t work in that system. Instant runoff is about as close as it seems practical to me to get to a more sophisticated vote system. It would at least allow some vote aggregation in multiple candidate contexts.