Back to questioning the Muon2 rules

[muon2]

You have macrochopped Warren and the erosity is much higher than you think. Once it is macrochopped we consider the subunits of the macrochop. In this case it would be the precincts within Warren. The erosity just across the two parts of Warren is something like 13 or 14 given the number of precincts that are connected by road there. If you try to avoid touching Center Line it will only make the erosity that much worse through the very stair steps you describe.

As I look at it, the line across Warren isn't that straight. The better plan would fill that last precinct surrounding Center Line with blue Warren, then shift the northwest blue precinct over to pink Warren. Still both are gross compared to any plan that keeps Warren whole or at least to a simple chop.

[muon2]

A macrochop is 5% of the population of the district so any unit under 10% of the district can't be macrochopped. Warren in 2010 was 134K or 19% of a whole district of 706K so it can be macrochopped. When we divided Detroit they were in subunits that varied from 53K to 88K, and though the largest could be macrochopped, most chops would not exceed the 35K threshold for a macrochop. If the a Detroit subunit was macrochopped then we went to precincts. So Warren is closer to being like two Detroit neighborhoods.

In other jurisdictions we have looked for governmentally-designated areas that are typically between 5-10% of a CD. If there is a agreed upon subunit for cities over 10% of a CD then we would use that. If there isn't then the default is the precinct.

[muon2]

The preexisting political lines are not expected to be pretty, but they do recognize real jurisdictions. The important idea is to have a previously agreed hierarchy of subunits for each state - from county down to census block.

The hierarchy in MI looked like:
County
City/Township
Planning Neighborhoods (Detroit only)
Precinct
Census Block (not usable in DRA)

The hierarchy in WA looked like
County
City/School District (approximate in DRA)
City-defined Neighborhoods (Seattle only)
Precinct
Census Block (not usable in DRA)

School districts were used in WA because there was no township government that completely covered and divided up all the unincorporated areas in a county. I'm not sure that school districts make the most sense for units like Warren. If there really is a need for a layer between city and precinct for cities in excess of 10% of a CD, I think zip codes would be better here.

In any case, it seems that what you were trying to do in the OP was a political gerrymander. The rules are supposed to make that task hard by penalizing plans that may look reasonable, but in fact chop up locales to achieve political goals. If you want to avoid the macrochop (35K and up) why not put Warren and Center Line in the blue CD minus a nice rectangular chop out of the NE corner of Warren for the pink?

[muon2]

I forgot the 2020 adjustment to the macrochop threshold.

The courts have been moving in the direction of allowing districts that can elect the candidate of choice even when there is not 50% BVAP. The 7th circuit was ok with that in IL legislative districts in the 2010 cycle (46% in one case). In general SCOTUS doesn't like bright lines in redistricting cases since they fear parties will figure out how to gerrymander around any safe harbor they provide. The VA case was a clear example of that softening line. I think that a 48% BVAP in MI will probably be ok in 2020 unless the Trump picks for SCOTUS totally redo the interpretation of performing minority districts in the next remap cycle. It seems more likely to me that they will move to greater deference to the legislature, not tighter requirements on minority districts.

Even if there is a move to tighter requirements for minority CDs, I think the rules are ok. Every plan will have the same constraint to meet the VRA and if that means chops are needed, the plan with the most judicious chops under the rules should be rewarded. It just may be that a partisan Pub plan won't get that reward.