Tuesday, April 19, 2011

Michigan Redistricting: State House Part II: Oakland and Genesee

The first part of my analysis of redistricting the Michigan state house focused on Wayne County. That article contains the basics on the rules that any map must follow.

Michigan Redistricting: State House Part I: Wayne County

In particular, a good map avoids county breaks when possible. We have seen that districts in Wayne County can be drawn to avoid a break. This is also true for Washtenaw, Livingston, Ingham, and Lapeer Counties.

Part II begins by considering Oakland County. It is technically possible to avoid breaking Oakland, but only by significantly overpopulating its districts, which would lead to more city/township breaks, which must also be avoided.

Currently, Oakland has about 13.2 districts, sharing one township with a district mostly contained in Livingston County. Population growth in Livingston means that it no longer needs to be broken. The ideal number of districts for Oakland is now 13.38.

Oakland borders Genesee to the northwest. Genesee currently has five districts. It just barely avoided a break in 2000 by having district populations well under the ideal and just barely above the threshold. Population loss in Genesee, particularly in Flint, means that Genesee must now be broken. Its ideal number of districts is now 4.74.

Hence it works well the combine Oakland and Genesee so that one house district contains parts of both of them. These counties will share 18 districts with an ideal population of 90453.

See the current map here: MICHIGAN'S 110 HOUSE DISTRICTS

Populations were quite stable in southeastern Oakland, and my proposed districts don’t change much from the current map. The city of Pontiac did lose about 8000, and Southfield lost 6500. Both are democrat, black-majority areas. Population grew in north and west Oakland, leading to a reshuffling of the districts there. Among the biggest gainers were Novi, Commerce, and Oxford.

Meanwhile, population dropped by 10000 in Genesee. Flint lost 22500, and Flint, Mt. Morris, and Genesee townships each lost about 2000 meanwhile, Grand Blanc Township, a Republican area, gained about 8000.

There are currently two black-majority districts based in Southfield and Flint and my map easily maintains them.

Oakland County currently has six democrats and 7.2 Republicans. Only one district, the West Bloomfield/Commerce district (39) has changed parties all decade. That district is a tossup and the Waterford district (43) leans Republican. The rest are safe for their respective parties.

Genesee has four democrats and one Republican. The democrats are all safe and the southern tier (Grand Blanc, Fenton) district 51 leans Republican.

Given population shifts, a reasonable goal for Republicans is to win back district 39, secure Waterford (43) and draw a Republican district containing parts of Genesee and Oakland. My proposed map accomplishes all three goals. The Pontiac district (29) loses Auburn Hills and adds about 30000 people from democrat areas of West Bloomfield. The Waterford district loses its part of West Bloomfield and adds Springfield. (These townships do share more than a point in common due to an offset, i.e. they don’t quite align horizontally.) The new district 50 contains the eastern townships of Genesee and Thetford plus Brandon and Oxford from Oakland (it also uses an offset). This district should lean Republican.

Here are the maps. Amazingly, there are only three city/township breaks. They are in West Bloomfield, Oakland Township, and Flint. This is the absolute minimum possible.

Ratings and descriptions for the map:
26. Safe D [Royal Oak, Madison Heights]
27. Safe D [Oak Park, Ferndale, Hazel Park]
29. Safe D [Pontiac, SE West Bloomfield]
35. Safe D [Southfield]
37. Safe D [Farmington]
38. Safe R [Novi, Lyon]
39. Lean R(+) [W West Bloomfield, Commerce, Wixom]
40. Safe R [Bloomfield, Auburn Hills]
41. Safe R [Troy, Clawson]
43. Safe R(+) [Waterford, Springfield]
44. Safe R [Milford, Highland, White Lake, Rose, Holly, Groveland]
45. Safe R [Rochester, S Oakland Twp]
46. Safe R [Independence, Orion, Addison, N Oakland Twp]

34. Safe D [Flint]
48. Safe D [Burton, Genesee, Mt. Morris, Vienna]
49. Safe D [western column, Flint Twp]
50. Lean R(+++) [eastern column, Thetford, Brandon, Oxford]
51. Lean R [Grand Blanc, Mundy, Fenton]

Hence we have the following ratings:

Rating: SR/LR/TU/LD/SD
Old……. 6 / 2 / 1 / 0 / 9
New…… 7 / 3 / 0 / 0 / 8

Previous articles on Michigan redistricting:
Michigan Congressional Redistricting: Two Possible Maps
Michigan Redistricting: Two Possible State Senate Maps
Michigan Redistricting: State House Part I: Wayne County

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