US House Redistricting: Iowa

[Tintrlvr]

Here’s the 538 GOP gerrymander:

https://davesredistricting.org/join/60cda9dc-5f6e-491b-a0dd-232b9563018c

It looks like they could make a Dem vote sink in east IA to shore up the other three districts, plus crack Des Moines between IA-3 and IA-4.

Obviously it’s outdated and I don’t know what maps the new population would make.

You can't split counties in Iowa by law (unless necessary for population equality, but in Iowa it's not because of the plethora of tiny counties).

[Tintrlvr]

Here’s the 538 GOP gerrymander:

https://davesredistricting.org/join/60cda9dc-5f6e-491b-a0dd-232b9563018c

It looks like they could make a Dem vote sink in east IA to shore up the other three districts, plus crack Des Moines between IA-3 and IA-4.

Obviously it’s outdated and I don’t know what maps the new population would make.

You can't split counties in Iowa by law (unless necessary for population equality, but in Iowa it's not because of the plethora of tiny counties).

Didn’t know that. Would it be possible to make a map with R-leaning districts?

They’d probably combine Polk with Story for a D vote sink. Then the leftovers of IA-3 can become part of the new IA-4 and the eastern remnants of the old IA-4 can become part of IA-1.

Also, is it possible to put Linn, Johnson, and Scott in one district so shore up IA-1 for the GOP?

Basically the way redistricting works in Iowa is that there is an extremely strict formula for how districts can be shaped, and counties can't be split. So they run a program that spits out a bunch of legally acceptable maps, which are created totally algorithmically, and then the legislature picks from among those options. The legislature can also ignore the program's choices and create their own, but they still have to follow the extremely strict rules about district shape (in particular, I believe the rule is something like that districts must all have a low ratio of their north-south axis to their east-west axis, but more mathematically determined than that), so there would in practice be no more than tiny deviations from what the program spits out (usually just switching one <2,000 person county for another).

This in practice means that gerrymandering is not really possible in Iowa, and you sort of get what you get by the population distribution. So you can't really actively try to favor one party over another. The Democrats did get pretty lucky in the 2010 map, especially given later trends in the state, but it was really just luck. Also, if you read earlier in the thread, it was considered a favorable map for the Republicans at the time.

[Tintrlvr]

Not sure if it would be legal, but here is my attempt at an R gerrymander while keeping counties whole



Basically one dem sink, one tossup district and 2 safe R districts based on 2016. Based on 2012 the 2 R districts become competitive while the tossup district becomes safe D

They would probably consider it non-compact.

And if they can come up with another plan that has more precise population equality they will knock out your plan (if your plan has 1000 deviation between districts, it will be considered to be lousy).

Yeah, in Iowa they typically have deviations under 100 with no county splits. And the Des Moines-Iowa City district in particular definitely has too large of a width-height ratio to be considered.

[Tintrlvr]

Here’s the 538 GOP gerrymander:

https://davesredistricting.org/join/60cda9dc-5f6e-491b-a0dd-232b9563018c

It looks like they could make a Dem vote sink in east IA to shore up the other three districts, plus crack Des Moines between IA-3 and IA-4.

Obviously it’s outdated and I don’t know what maps the new population would make.

You can't split counties in Iowa by law (unless necessary for population equality, but in Iowa it's not because of the plethora of tiny counties).

Didn’t know that. Would it be possible to make a map with R-leaning districts?

They’d probably combine Polk with Story for a D vote sink. Then the leftovers of IA-3 can become part of the new IA-4 and the eastern remnants of the old IA-4 can become part of IA-1.

Also, is it possible to put Linn, Johnson, and Scott in one district so shore up IA-1 for the GOP?

Basically the way redistricting works in Iowa is that there is an extremely strict formula for how districts can be shaped, and counties can't be split. So they run a program that spits out a bunch of legally acceptable maps, which are created totally algorithmically, and then the legislature picks from among those options. The legislature can also ignore the program's choices and create their own, but they still have to follow the extremely strict rules about district shape (in particular, I believe the rule is something like that districts must all have a low ratio of their north-south axis to their east-west axis, but more mathematically determined than that), so there would in practice be no more than tiny deviations from what the program spits out (usually just switching one <2,000 person county for another).

This in practice means that gerrymandering is not really possible in Iowa, and you sort of get what you get by the population distribution. So you can't really actively try to favor one party over another. The Democrats did get pretty lucky in the 2010 map, especially given later trends in the state, but it was really just luck. Also, if you read earlier in the thread, it was considered a favorable map for the Republicans at the time.

So Iowa Republicans are better off focusing on redrawing the legislature.  

I think the rules for the legislature are the same, although you have to split counties given the district sizes (but a similar rule applies for municipality splits, though again in a few places you do have to split municipalities, such as Des Moines).

[Tintrlvr]

Looking at the alternatives from the computer program, I don't see how the Republicans could have done materially better within the narrow confines of what's permissible in Iowa. All of the options are roughly the same, and some are noticeably worse for the Republicans. The geography is not so favorable for the Republicans since the strong R areas in the west of the state can't really be used to sink either Des Moines or the Democratic towns in the east.

Nice for the Democrats that the end result is likely D+1, R-1.