In short, heterogeneous coalitions do backfire electorally, but mainly because voters feel distant from the coalition’s overall composition, not just because they dislike a particular partner party. More here: papers.ssrn.com/sol3/papers.....

Zooming in on this case, @ugurozdemir.bsky.social and I have examined when too much diversity in pre-electoral coalitions backfires; that is, when they reduce support from voters who might have backed any of the constituent parties if they had run separately.

A case in point for this decision problem is the 2023 Turkish general election. A highly diverse opposition alliance united behind a single presidential candidate, while the main opposition party (CHP) opened its parliamentary lists to candidates from smaller allied parties.

Thanks so much for visiting, Ben --you're doing excellent work!

Haha, you just caught me ;) I'm not from Baden-Württemberg, though.

2) As Manes already pointed out, support in the cities was among the lowest in 2019. So the vote share was already comparatively low there. Also in the 2019 election, PiS support did not substantially increase in the cities, but almost everywhere else.

I was surprised by this as well. I can think of two factors. 1) In relative terms, both cities and more rural regions welcomed refugees: Powiat Grójecki, Wrocław, Powiat Pruszkowski, Przemyśl, and Powiat Rawski, along with Warsaw, saw the largest inflow relative to their populations.

The party could win additional % across the country in 2019 compared to 2015, so the level of support was quite high in 2019 even in the Northeast. But I agree that floor effects may be present.

This is an important point. Just to provide a bit more context: In 2019, PiS performed well even in the Northeast.

The 2023 election was fundamentally different; this time, the opposition, not PiS, mobilized more voters.

There was already a substantial increase in turnout in the 2019 elections, during which PiS gained compared to 2015. These electoral gains were mainly related to improved economic conditions and public goods provision (see papers.ssrn.com/sol3/papers....).

and 3) the relative number of Ukrainian refugees seems unrelated to PiS punishment.

2) increased turnout harmed PiS in all regions,

1) PiS lost particularly in 2019 strongholds,