District sizes and how they impact Dem fortunes

[President Punxsutawney Phil]

In which states does the geography get worse for Democrats as the districts get smaller? In which states do they get better?

[DINGO Joe]

virtually ever state is better when smaller.  Unless your trying to do some extreme gerrymander

[Buffalo Mayor Young Kim]

Pretty much Maryland gets slightly worse, but that's about it.
The reality in most places is that allot of Republican districts are anchored by Democratic-leaning smaller cities that get burried by surrounding rurals/suburbs, while the dark blue districts centered on major cities would largely be split in two without partisanship changing much.

[Del Tachi]

Theoretically, the more districts you add the more proportional and outcome you could achieve no?  Tiebout model and all that

[Skill and Chance]

When they are not aggressively drawn to benefit one party, larger districts help Democrats in the most urbanized states (see the Dem domination of the CA Senate, which has districts bigger than federal CDs) and hurt everywhere else.  This is true even if the highly urbanized state is GOP leaning today (see FL Senate, TX BOE).

Where it gets complicated is that many states have stricter rules for redistricting in the lower house than in the state senate (generally because state senate districts weren't population-based at all pre-Baker v. Carr).  This can make it look like Democrats do better in the lower house when it's actually a consequence of the maps. 

[Stuart98]

Theoretically, the more districts you add the more proportional and outcome you could achieve no?  Tiebout model and all that

Not necessarily, if votes for one party are much more packed than votes for the other. You can get a proportional 1D 2R result in Utah if you have only 3 districts, while with 100 districts a typical democratic candidate (eg Wilson 2018) will only carry about a quarter of districts.

[Boss_Rahm]

Pennsylvania has 203 state house districts, and I don't think it's possible to draw a map that isn't Republican-biased. Maps with fewer districts tend to be Republican-biased as well, but there's more room for idiosyncrasies. For instance, at 9 districts it's pretty natural to draw a 5D-4R map, with Democrats getting 3 Philly-area districts, 1 Pittsburgh-area district, and 1 NEPA + Lehigh Valley district.

[Former President tack50]

To use a random state, I think Nevada is a state where there are interesting "jumps" depending on to what degree you can pack the areas that are not Reno/Las Vegas. Using 2016-PRES as the reference point and the following benchmarks:

1 District: Tossup
2 Districts: 1 Safe D, 1 Likely R
3 Districts: 2 Safe D, 1 Safe R
4 Districts: 2 Safe D, 1 tossup, 1 Safe R
5 districts: 2 Safe D, 1 tossup, 1 Likely R, 1 Safe R
6 districts: 3 Safe D, 2 tossup, 1 Safe R

Or if you want to look at the median district:

1: Clinton+2
2: Clinton+8
3: Clinton+12
4: Clinton+5
5: Clinton+0
6: Clinton+8.5