US House Redistricting: North Carolina

[JacobNC]

Since I'm a n00b at Apple Computers and I haven't figured out picture editing yet, this is the best you're gonna get:



Not too erose, eh?  The 1st is black plurality and it locks up with the 3rd quite nicely.  Most of those erose peninsulas are (or were) required by the VRA anyway.

Edit: the numbers are a little hard to read; among VAP it's 46.9 black and 46.5 white.

[muon2]

My biggest objection is to your CD 9. A year ago we generally concluded that connecting two whole counties by means of a bridge through a third is an invitation to gerrymandering and should be avoided. Having a CD wholly in Mecklenburg isn't worth the erose shape of CD 9.

Yes, the bridge is a bit awkward, but as someone who lives in CD9, I think putting Gaston and Union Counties together is a good CoI.

It may be a CoI, but it's a bad policy and invites mischief if allowed in general. From a purely geographic view, the bridge county is chopped either way, so why choose the plan with more erosity? As we try to find rules that push maps to be fair, it's clear that geography has to be considered ahead of subjective factors. CoI's can be recognized, but to do so requires it be made part of an objective measure of fairness that can be balanced against other objective geographical measures.

By this plan you are suggesting that the suburban/urban division should be elevated as a CoI. If so the impact should be balanced against the negative effect of forcing a partisan division. Bridges in urban areas historically get used to gerrymander two safe seats favoring opposite parties. A split urban county might produce more competitive districts.

I think contiguity of the whole urban area is more important than preserving an urban/suburban split, and that is embodied by the recognition of urban county clusters. To reduce the potential to overly dilute an urban county and create a gerrymander that way, maps are ranked as less fair if they use more than the minimum number of districts to cover a whole urban cluster.

[muon2]

Since I'm a n00b at Apple Computers and I haven't figured out picture editing yet, this is the best you're gonna get:



Not too erose, eh?  The 1st is black plurality and it locks up with the 3rd quite nicely.  Most of those erose peninsulas are (or were) required by the VRA anyway.

Edit: the numbers are a little hard to read; among VAP it's 46.9 black and 46.5 white.

That's a reasonably compact shape, but as drawn you would be challenged to justify why it is required by the VRA. For a district to be required there must be a population of a single minority in excess of 50% VAP in a compact geographic area capable of being drawn in a single district. This district can't make that case.

To make the case you must argue that a district involving a split into Raleigh and/or Durham that gets over 50% BVAP is compact. Then you can draw a district like yours and claim that the minority can elect the representative of their choice though minority coalitions or white crossover votes. However, in that case one no longer needs a black plurality, just a large enough black population that they would be likely to control both the primary and general elections and elect the representative of their choice.

[Sol]

I understand what you're saying about bridges inviting mischief. But there should definitely be a Mecklenburg-based district- it is a strong COI relative to the suburbs. Perhaps there could be a method to grant exemptions to rules like this that mess up COIs?

[Sol]

What about this for the Charlotte UCC? Both CD9 and CD12 are vaguely competitive (the former would probably be a total tossup by 2020).

[muon2]

What about this for the Charlotte UCC? Both CD9 and CD12 are vaguely competitive (the former would probably be a total tossup by 2020).

The five counties north and east of Mecklenburg (Iredell, Rowan, Cabarrus, Stanly, Union) are less than 1% larger than a CD. They also make a much better connection than the one in your map. Then bring the Gastonia CD into N and SW Mecklenburg to leave a whole CD that keeps most of Charlotte intact. That also keeps the whole UCC in 3 CDs.

[JacobNC]

I would make the 12th district as compact as possible and give the Huntersville/Lake Norman area of Northern Mecklenburg County and the Matthews/Pineville area of Southern Mecklenburg to the 9th.

[Sol]

How does this map look? Eastern NC is screwy, of course.



Charlotte:

[muon2]

How does this map look? Eastern NC is screwy, of course.



Charlotte:

Much better around Charlotte (though you sort of rely on a bridge since the border between Iredell and Lincoln is a reservoir with no crossing). Now if you can fix the crazy shape of CD-3 you'll be even better.

[jimrtex]

Charlotte:

Much better around Charlotte (though you sort of rely on a bridge since the border between Iredell and Lincoln is a reservoir with no crossing). Now if you can fix the crazy shape of CD-3 you'll be even better.

(Most of) the border between Iredell and Lincoln is within the Charlotte Urbanized Area.  The urbanized area cross below the dam and then extends northward along the western shore of Lake Norman.  There are some rules for enclosing indentions which bring that part of Lake Norman into the urbanized area.

In addition, the bridge on NC 150 is only about 4 miles north of the Catawba-Lincoln line with NC 150 going southwestward directly toward Lincoln.   That crossing and the crossing below the dam provide adequate connectivity.

And I'd view that map as placing the northern and western counties of the UCC (Iredell and Gaston) with a significant part of Mecklenburg, and then adding Lincoln.   The Mecklenburg portion of the district must be close to 300,000.  At around 30% of the county and 40% of the district, I don't think it can be considered a bridge at all.

[muon2]

Charlotte:

Much better around Charlotte (though you sort of rely on a bridge since the border between Iredell and Lincoln is a reservoir with no crossing). Now if you can fix the crazy shape of CD-3 you'll be even better.

(Most of) the border between Iredell and Lincoln is within the Charlotte Urbanized Area.  The urbanized area cross below the dam and then extends northward along the western shore of Lake Norman.  There are some rules for enclosing indentions which bring that part of Lake Norman into the urbanized area.

In addition, the bridge on NC 150 is only about 4 miles north of the Catawba-Lincoln line with NC 150 going southwestward directly toward Lincoln.   That crossing and the crossing below the dam provide adequate connectivity.

And I'd view that map as placing the northern and western counties of the UCC (Iredell and Gaston) with a significant part of Mecklenburg, and then adding Lincoln.   The Mecklenburg portion of the district must be close to 300,000.  At around 30% of the county and 40% of the district, I don't think it can be considered a bridge at all.

That's why I said "sort of".

In the strictest sense a bridge refers to a county fragment use to link two discontiguous whole counties that cannot otherwise be linked using whole counties in the district. While Iredell and Lincoln are contiguous in a geographic sense, their border is short and entirely in Lake Norman. I don't need to rehash our debates about using roads outside of the counties in question to determine connectivity; we just won't agree.

[Miles]

Yes, muon, all your points against my CD9 are very good.

I think you will, but would you consider these to be bridges?

[muon2]

Yes, muon, all your points against my CD9 are very good.

I think you will, but would you consider these to be bridges?

In the strictest sense a bridge refers to a county fragment use to link two discontiguous whole counties that cannot otherwise be linked using whole counties in the district.

In both your examples Gaston is discontiguous to Cabarrus so the piece of Mecklenburg forms a bridge. I think you are putting too much weight on a CD entirely within a large county. From a chop perspective it doesn't help. It's more important to minimize the number of CDs that cover a metro as defined by a UCC.

[Sol]

I think that county chops should still penalized with large MSAs, although perhaps less so- this Mecklenburg example is one of many clear issues with that practice. In a way, in fact, it kind of does open the door to gerrymandering like-so:


which is obviously sub-optimal.

[Sol]

Also, here is a revised map. It neatens up CD3 and CD4 at the expense of CD1, which becomes majority white by VAP.

[muon2]

I understand what you're saying about bridges inviting mischief. But there should definitely be a Mecklenburg-based district- it is a strong COI relative to the suburbs. Perhaps there could be a method to grant exemptions to rules like this that mess up COIs?

CoI's are typically very subjective things, and its easy to use their existence to gerrymander. To that end, I'm only comfortable using CoIs that can be quantified like UCCs and MCCs, and existing political units like counties and munis.

That doesn't mean that a Mecklenburg-only CD can't be in the plan, it can be and if it gets to the appropriate body for consideration the local CoI may win the day. However, before it gets to that point the plan needs to be able to compete against other plans that chop Charlotte in other ways. I'm still curious as to the ability to make a plan with the five counties N and E of Mecklenburg then attach Gaston and the Mecklenburg fraction to counties to the west. If it can be done, it avoids this whole problem.

[Sol]

I don't think it's possible without impinging in on the Hickory UCC.

[traininthedistance]

I understand what you're saying about bridges inviting mischief. But there should definitely be a Mecklenburg-based district- it is a strong COI relative to the suburbs. Perhaps there could be a method to grant exemptions to rules like this that mess up COIs?

CoI's are typically very subjective things, and its easy to use their existence to gerrymander. To that end, I'm only comfortable using CoIs that can be quantified like UCCs and MCCs, and existing political units like counties and munis.

That doesn't mean that a Mecklenburg-only CD can't be in the plan, it can be and if it gets to the appropriate body for consideration the local CoI may win the day. However, before it gets to that point the plan needs to be able to compete against other plans that chop Charlotte in other ways. I'm still curious as to the ability to make a plan with the five counties N and E of Mecklenburg then attach Gaston and the Mecklenburg fraction to counties to the west. If it can be done, it avoids this whole problem.

I fiddled around with this a little bit and the problem you run into is that such a plan forces a split of Hickory-Lenoir-Morgantown, or Asheville (which also upsets the whole-county CD 11).

I happen to find the logic of an all-Mecklenburg district sufficiently compelling that I'm willing to accept the de facto Mecklenburg bridge of the proposed CD 9 here; in general I tend to prefer giving at least a little preference to plans that create whole districts inside of large counties, and the size and shape of the Charlotte UCC is such that you're going to have some sort of problem no matter what you do; my first inclination is to let the 150K-strong de facto Mecklenburg bridge happen on the grounds that a) the technical water connectivity of Iredell-Lincoln, b) the ability of such a plan to keep the Charlotte UCC in three districts, including one core and two hinterlands districts, and c) not screwing with Hickory-Lenoir-Morgantown, all work as mitigating factors that ought to make it acceptable.

I guess that, in general, I'm not particularly bothered by bridges when they are comprised of the balance of large metro counties that are otherwise entirely one district.  I expect that is somewhat loosey-goosey for you, though.

[Sol]

I understand what you're saying about bridges inviting mischief. But there should definitely be a Mecklenburg-based district- it is a strong COI relative to the suburbs. Perhaps there could be a method to grant exemptions to rules like this that mess up COIs?

CoI's are typically very subjective things, and its easy to use their existence to gerrymander. To that end, I'm only comfortable using CoIs that can be quantified like UCCs and MCCs, and existing political units like counties and munis.

That doesn't mean that a Mecklenburg-only CD can't be in the plan, it can be and if it gets to the appropriate body for consideration the local CoI may win the day. However, before it gets to that point the plan needs to be able to compete against other plans that chop Charlotte in other ways. I'm still curious as to the ability to make a plan with the five counties N and E of Mecklenburg then attach Gaston and the Mecklenburg fraction to counties to the west. If it can be done, it avoids this whole problem.

I fiddled around with this a little bit and the problem you run into is that such a plan forces a split of Hickory-Lenoir-Morgantown, or Asheville (which also upsets the whole-county CD 11).

I happen to find the logic of an all-Mecklenburg district sufficiently compelling that I'm willing to accept the de facto Mecklenburg bridge of the proposed CD 9 here; in general I tend to prefer giving at least a little preference to plans that create whole districts inside of large counties, and the size and shape of the Charlotte UCC is such that you're going to have some sort of problem no matter what you do; my first inclination is to let the 150K-strong de facto Mecklenburg bridge happen on the grounds that a) the technical water connectivity of Iredell-Lincoln, b) the ability of such a plan to keep the Charlotte UCC in three districts, including one core and two hinterlands districts, and c) not screwing with Hickory-Lenoir-Morgantown, all work as mitigating factors that ought to make it acceptable.

I guess that, in general, I'm not particularly bothered by bridges when they are comprised of the balance of large metro counties that are otherwise entirely one district.  I expect that is somewhat loosey-goosey for you, though.

Exactly.

It's Morganton though. [/pedant mode]

[jimrtex]

I think that county chops should still penalized with large MSAs, although perhaps less so- this Mecklenburg example is one of many clear issues with that practice. In a way, in fact, it kind of does open the door to gerrymandering like-so:


which is obviously sub-optimal.

I would control gerrymandering within UCC by not permitting double-spanning, where two or more districts contain parts of pairs go counties.  That is, the district boundaries should be generally parallel to county boundaries, rather than perpendicular.  In addition, there should be no more counties split than is the minimum.

So with your Hennepin-Anoka-Ramsey district, you could not have another district connect Hennepin and Anoka, nor Anoka and Ramsey, nor Ramsey and Hennepin.

[jimrtex]

Charlotte:

Much better around Charlotte (though you sort of rely on a bridge since the border between Iredell and Lincoln is a reservoir with no crossing). Now if you can fix the crazy shape of CD-3 you'll be even better.

(Most of) the border between Iredell and Lincoln is within the Charlotte Urbanized Area.  The urbanized area cross below the dam and then extends northward along the western shore of Lake Norman.  There are some rules for enclosing indentions which bring that part of Lake Norman into the urbanized area.

In addition, the bridge on NC 150 is only about 4 miles north of the Catawba-Lincoln line with NC 150 going southwestward directly toward Lincoln.   That crossing and the crossing below the dam provide adequate connectivity.

And I'd view that map as placing the northern and western counties of the UCC (Iredell and Gaston) with a significant part of Mecklenburg, and then adding Lincoln.   The Mecklenburg portion of the district must be close to 300,000.  At around 30% of the county and 40% of the district, I don't think it can be considered a bridge at all.

That's why I said "sort of".

In the strictest sense a bridge refers to a county fragment use to link two discontiguous whole counties that cannot otherwise be linked using whole counties in the district. While Iredell and Lincoln are contiguous in a geographic sense, their border is short and entirely in Lake Norman. I don't need to rehash our debates about using roads outside of the counties in question to determine connectivity; we just won't agree.

Within the UCC, Gaston is only connected to Mecklenburg, and Union is only slightly connected to Cabarrus.   While Iredell is connected to Rowan and Cabarrus, the functional connection is with Mecklenburg.

Functionally the urbanized area is like a starfish with western (Gastonia), northern, northeastern (Concord), southeastern, southern (Rock Hill, SC) arms.  To avoid using Mecklenburg as a "bridge", it would have to be split in 3 parts.

Taking a large chunk of the body and connecting to two arms is not really a bridge.  Mecklenburg must be split, and one district is wholly within the county, and the remnant is self contained and of substantial population, larger than either Iredell or Gaston.

I would make a distrinction between county fragments necessary for gross population equality (ie within multi-district regions), and those small chops that might be necessary to placate the SCOTUS (interregional).  Of course those bridges would not be possible under a system that first defines the regions, because the chop is necessary to make the region contiguous.

Here is the statement of our disagreement with regard to county contiguity.

We agree that regions and districts should be comprised of contiguous whole counties or parts of counties.  We agree that superficial contiguity should not be permitted.

Point contiguity is not permitted.  Contiguity across large bodies of waters is not permitted, unless there is a bridge or ferry that traverses the boundary.  For example Richmond and Queens, nor Nassau and Westchester in New York are not considered to be contiguous.  Also where there are substantial barriers to travel, such as the northern Cascades.

Where we disagree:

I would restrict near point contiguity, and I have provided a workable formula.  I would permit direct travel between counties, so long as it is not substantially through the main portion of oher counties.  Since districts are comprised of counties, contiguity is most significant, road connectivity is secondary.  I do not regard rivers, or reservoirs to be barriers, particularly if there is a nearby way to cross them.  If simplified boundary length is used for measuring compactness, regions that connect through narrow isthmuses will be heavily penalized. 

You would require true road without any incidental travel outside the two counties.

[muon2]

I understand what you're saying about bridges inviting mischief. But there should definitely be a Mecklenburg-based district- it is a strong COI relative to the suburbs. Perhaps there could be a method to grant exemptions to rules like this that mess up COIs?

CoI's are typically very subjective things, and its easy to use their existence to gerrymander. To that end, I'm only comfortable using CoIs that can be quantified like UCCs and MCCs, and existing political units like counties and munis.

That doesn't mean that a Mecklenburg-only CD can't be in the plan, it can be and if it gets to the appropriate body for consideration the local CoI may win the day. However, before it gets to that point the plan needs to be able to compete against other plans that chop Charlotte in other ways. I'm still curious as to the ability to make a plan with the five counties N and E of Mecklenburg then attach Gaston and the Mecklenburg fraction to counties to the west. If it can be done, it avoids this whole problem.

I fiddled around with this a little bit and the problem you run into is that such a plan forces a split of Hickory-Lenoir-Morgantown, or Asheville (which also upsets the whole-county CD 11).

I happen to find the logic of an all-Mecklenburg district sufficiently compelling that I'm willing to accept the de facto Mecklenburg bridge of the proposed CD 9 here; in general I tend to prefer giving at least a little preference to plans that create whole districts inside of large counties, and the size and shape of the Charlotte UCC is such that you're going to have some sort of problem no matter what you do; my first inclination is to let the 150K-strong de facto Mecklenburg bridge happen on the grounds that a) the technical water connectivity of Iredell-Lincoln, b) the ability of such a plan to keep the Charlotte UCC in three districts, including one core and two hinterlands districts, and c) not screwing with Hickory-Lenoir-Morgantown, all work as mitigating factors that ought to make it acceptable.

I guess that, in general, I'm not particularly bothered by bridges when they are comprised of the balance of large metro counties that are otherwise entirely one district.  I expect that is somewhat loosey-goosey for you, though.

If the rules are loose they are easy prey for gerrymanders. Here's a version that avoids bridges, covers the UCC with 3 CDs, and only has one county chop other than Mecklenburg. The Asheville and Hickory UCCs are left alone. The Charlotte CD already spilled into the eastern suburbs of Mathews and Mint Hill, and this version adds 31 K more by picking up Weddington and Marvin. I doubt the impact of the Union incursion on your CoI is very much.

[Miles]

If the rules are loose they are easy prey for gerrymanders. Here's a version that avoids bridges, covers the UCC with 3 CDs, and only has one county chop other than Mecklenburg. The Asheville and Hickory UCCs are left alone. The Charlotte CD already spilled into the eastern suburbs of Mathews and Mint Hill, and this version adds 31 K more by picking up Weddington and Marvin. I doubt the impact of the Union incursion on your CoI is very much.

As someone who's still fan of the bridge approach for CD9, I actually like this map a lot

I'd maybe swap around a few precincts in Charlotte, but good job, muon!

[Miles]

muon, do you like this map?

[muon2]

muon, do you like this map?

I don't like the Raleigh area much at all. It would help me to understand your goals there, especially as it relates to .

Do you believe that an area including a 50% BVAP is sufficiently compact to require a district under section 2?

If it is, then the numbers must reflect the ability of the black population to elect a representative of choice. So what BVAP and Dem% are large enough for you? BVAP doesn't necessarily have to be 50% if there are enough other Dems to elect that candidate out of the primary. Pubs use 50% because that is a safe harbor, but Dems have used numbers down to 45% BVAP when they have negotiated with the minority groups.

If it isn't, then you are looking to maintain a district where a black CoI is one of the factors you are using. How do you want to define that CoI along with other factors to avoid the charge the race was the predominant factor in drawing the district?