Colorado Redistricting Mildly Favors GOP

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The big event of the 2011 legislative session in Colorado will be the redistricting of its seats in Congress, the state senate, and the state house (CU Regent and State Board of Education seats are derivative of those for Congress).

The Process

A deal on Congressional redistricting will require the agreement of the probably Republican controlled state house (the split is 33-32 and one GOP seat of the 33 is still technically in play), and a Democratic party controlled state senate. This leaves the Democrats and Republicans on equal footing.

The state legislative seats are redrawn by an eleven member reappoprtionment commission (Article V, Section 48, Colorado Constitution) subject to some rather specific guidelines (Article V, Sections 45, 46, and 47). Democratics and Republicans get one seat each from the state house and state senate (major party status in the last election isn't relevant to this determination), Governor Hickenlooper gets three appointments, and Chief Justice of the Colorado Surpeme Court Michael Bender gets four appointments. No more than six members can be member of the same political prty, and there are also geographical diversity requirements and a limit of four members who are state legislators. The Colorado Supreme Court then pre-approves the constitutionality of the map. Realistically, Democrats will have six rather than five seats, and the judicial appointees will not be political extremists, so this favors Democrats over Republicans, but only mildly.

The Change In Population

Basically, neither party has a truly decisive advantage in the process this time around. And, this gives particular importance to the changes in population that have taken place in the last decade. Simply put, there has been more population growth in counties that leaned Republican in 2010 than there has been counties that leaned Democratic in 2010. The population numbers below are from 2000 to 2009, but will be very close to the 2010 census figures.

Intensity of partisan support, I measure using the relative Bennet-Buck vote, since this race was very nearly a tie, and hence roughly captures the current political divide betwen the two political parties and is appropriate to use as an index of partisan strength in each county.

While counties that favored Democrats grew more than counties that favored Republicans, population growth was weak in counties that intensely favor Democrats, while population growth was strong in counties that intensely favor Republicans.

Counties that supported Republican Ken Buck in 2010 gained 339,644 people, and adjusted for partisan intensity that is an expected gain of 85,282 votes relative to 2000. Counties that supported Democratic Michael Bennet in 2010 gains 344,660 people, and adjusted for partisan intensity that is an expected gain of 44,987 votes relative to 2000.

Thus, counties that supported Bennet accounted for 50.4% of population growth in Colorado, but counties that supported Buck supported him almost twice as intensely as counties that supported Bennet. So, new state legislative seats in Republican areas are more likely to go to Republicans since Republican advantages are decisive in those areas, than state legislative seats in Democratic areas which will probably be split more evenly betwen the parties because they are more competitive districts.

The redistricting effect in favor of Republicans will be equivalent to something on order of a two percentage point shift in the popular vote effect for the GOP in existing state legislative districts, which would have given both houses of the Colorado General Assembly to Republicans in this year's election.

Politically, first Denver ring suburbs that used to be considered Republican territory, like Adams, Arapahoe, Broomfield and Jefferson counties have swung towards Democrats and become narrowly Democratic leaning, which has muted the impact of significant population growth in these counties on the political balance in the state. Slight swings in partisan support in these suburbs make or break any candidate for statewide office, and these suburbs are likely to be home to most of the swing districts when redistricting is complete in 2012.

Congressional Redistricting Strategy

In Congressional redistricting, it is almost impossible to draw seven districts in Colorado without creating at least two safe Democratic districts (basically Denver-Boulder, which currently are in CO-1 and CO-2) and at least two safe Republican Districts (basically Highlands Ranch to Colorado Springs, which currently are in CO-5 and CO-6).

Colorado currently has three districts that could be competitive: CO-3 (Pueblo, the San Luis Valley and the Western Slope) and CO-4 (the rural front range and Fort Collins) were seats that had been held by Blue Dog Democrats prior to this year's election and are now held by Republicans. CO-7 is a district of first ring suburbs to the North of Denver that was originally held by Republican Bob Beauprez and now is held by Democrat Ed Perlmutter.

The most favorable arrangement for the Democrats that I've been able to envision that doesn't require a truly extraordinary Blue Dog Democrat like Ken Salazar to hold, would have four leans Democratic Districts: one district with West Denver and most of Jefferson County, one district with East Denver and Aurora, one district with Boulder, Broomfield, Western Adams County and part of Fort Collins, and one district with Pueblo, the San Luis Valley, some of Jefferson County and most of the mountain resort counties. This would leave Republicans with one district centered in Colorado Springs, one centered in Douglas County and Eastern Adams and Arapahoe Counties, and one with the rest of Fort Collins, Greeley and the rest of rural Colorado.

Realistically, with Republicans at the bargaining table and both parties interested in incumbent protection, a Congressional redistricting plan the protects the three incumbent Democrats (CO-1, CO-2 and CO-7) and protects the incumbent Republicans in CO-5 and CO-6, seems very likely, so the tricky part will be how to draw districts in the rural part of the state covered by CO-3 and CO-4 and held by freshman Republicans right now.

Republicans will probably try to make both districts roughly equally safe for the freshmen Republicans in those seats.

Democrats would probably be best advised to try to sacrifice one of those seats (probably CO-4) making it more safe for Republicans by removing some of Fort Collins from the district, while trying to make the other (probably CO-3) more competitive with a candidate like John Salazar or Ken Salazar in mind to contest it. Democrats would probably do that by trying to increase the share of resort counties in CO-3 and decreasing the share of Larimer County in CO-4, while increasing CO-4's share of rural Colorado.

Intraparty and Bipartisan Impact

For the Democratic Party, about 85% of its gains from population growth are from metro Denver, with much of the rest in resort communities and Pueblo. Democratic counties in the San Luis Valley are growing less politically important to Democrats. The Democratic party is increasingly a party of higher population density urban areas.

For the Republican party, about 84% of its gains from population growth are from greater Colorado Springs to Highlands Ranch, and from North of Denver in the vicinity of Greeley. Most of the rest of its growth was in the North-South corridor on the Western Slope from Delta to Grand Junction. Agricultural counties on the Front Range are becoming less politically important to Republicans. The Republican party is increasingly a party of exurbs and small to medium sized cities.

The 2010 census in Colorado has produced a bipartisan shift of power away from rural areas and towards cities and suburbs.

The Data

The raw data is below:

The counties that favored Republicans (in percentages and raw numbers of population growth, Bennet lead in percentage points, intensity adjusted impact):

1. Douglas +64% (+112,459) -25 (-30,615)
2. Weld +41% (+73,823) -21 (-15,503)
3. Mesa +26% (+29,838) -28 (-8,227)
4. Montrose +24% (+7,980) -43 (-3,431)
5. Elbert +17% (+3,415) -52 (-1,776)
6. El Paso +17% (+87,613) -27 (-23,656)
7. Park +15% (+2,239) -11 (-236)
8. Custer +14% (+497) -44 (-219)
9. Delta +13% (+3,488) -32 (-1116)
10. Rio Blanco +9% (+548) -10 (-55)
11. Montezuma +7% (+1,538) -29 (-446)
12. Moffat +6% (+796)
12. Chaffee +6% (+914) -2 (-18)
13. Teller +6% (+1,130) -33 (-373)
14. Dolores +5% (+96) -26 (-25)
15. Kit Carson +5% (+391) -43 (-168)
16. Fremont +4% (+1,670) -26 (-334)
17. Morgan +3% (+679) -24 (-163)
18. Logan + 1% (+268) -28 (-75)
19. Phillips 0% (-8) -37 (+3)
20. Yuma -1% (-107) -42 (+45)
21. Washington -10% (-506) -52 (+263)
22. Prowers -10% (-1,501) -30 (+450)
23. Lincoln -15% (-918) -43 (+395)
24. Baca -18% (-794) -44 (+349)
25. Cheyenne -22% (-485) -55 (+267)
26. Kiowa -24% (-384) -46 (+177)

Total Gain in GOP counties: 324,679
Total Gain in GOP counties adjusted for intensity of GOP support: 84,465

Counties that supported Hickenlooper but not Bennet:

1. Garfield +29% (+12,507) -3 (-375)
2. Archuleta +26% (+2,532) -20 (-506)
3. Crowley +16% (+885) -16 (-142)
4. Grand +12% (+1,469) -8 (-118)
5. Mineral +10% (+81) -4 (-3)
6. Bent +9% (+562) -10 (-56)
7. Hinsdale +4% (+31)
8. Rio Grande -7% (-832) -10 (+83)
9. Otero -8% (-1,641) -10 (+164)
10. Jackson -13% (-208) -29 (+60)
11. Sedgewick -15% (-421) -18 (+75)

Total Gain in Mixed Counties: 14,965
Total Gain in mixed counties adjusted for intensity of GOP support: 818

Total Gain in Buck counties: 339,644
Total Gain in Buck counties adjusted for intensity of GOP support: 85,282

The counties that favored Democrats:

1. Broomfield +43% (+16,797) +2 (+336)
2. Eagle +29% (+11,994) +10 (+1199)
3. Ouray +23% (+860) +5 (+43)
4. Adams +21% (+77,137) +7 (+5400)
5. Saguache +20% (+1,180) +21 (+248)
6. Routt +19% (+3,779) +18 (+680)
7. Larimer +19% (+46,888) +1 (+469)
8. Gilpen +18% (+857) +6 (+51)
9. La Plata +17% (+7,523) +4 (+301)
10. Arapahoe +16% (+77,393) +3 (+2,322)
11. Summit +16% (+3,691) +23 (+849)
12. San Miguel +15% (+964) +43 (+415)
13. Pueblo +11% (+15,752) +12 (+1,890)
14. Denver +10% (+55,709) +46 (+25,626)
15. Gunnison +10% (+1,394) +13 (+181)
16. Pitkin +8% (+1,171) +42 (+492)
17. Las Animas +5% (+813) +10 (+81)
18. Boulder +4% (+12,194) +37 (+4,512)
19. Alamosa +3% (+458) +14 (+64)
20. Lake +3% (+234) +19 (+44)
21. Jefferson +2% (+9,866) +2 (+197)
22. San Juan -1% (-3) +12 (0)
23. Huerfano -4% (-304) +12 (-36)
24. Clear Creek -7% (-616) +11 (-68)
25. Conejos -7% (-556) +14 (-78)
26. Costilla -14% (-515) +45 (-231)

Total Gain in Democratic Counties: 344,660
Total Gain in Democratic counties adjusted for intensity of Democratic support: 44,987

Counties Ranked By Raw Population Growth adjusted For Intensity of Dem Support

1. Douglas -30,615
2. El Paso -23,656
3. Weld -15,503
4. Mesa -8,227
5. Montrose -3,431
6. Elbert -1,776
7. Delta -1,116
8. Archuleta -506
9. Montezuma -446
10. Garfield -375
11. Teller -373
12. Fremont -334
13. Park -236
14. Costilla -231
14. Custer -219
15. Kit Carson -168
16. Morgan -163
17. Crowley -142
18. Grand -118
19. Conejos -78
20. Logan -75
21. Clear Creek -68
22. Bent -56
23. Rio Blanco -55
24. Huerfano -36
25. Dolores -25
26. Chaffee -18
27. Mineral -3
28. San Juan 0
29. Moffat (omitted, no material effect on overall result)
30. Hinsdale (omitted, no material effect on overall result)
31. Phillips +3
32. Ouray +43
33. Lake +44
34. Yuma +45
35. Gilpen +51
36. Jackson +60
37. Alamosa +64
38. Sedgewick +75
39. Las Animas +81
40. Rio Grande +83
41. Otero +164
42. Kiowa +177
43. Gunnison +181
44. Jefferson +197
45. Saguache +248
46. Washington +263
47. Cheyenne +267
48. La Plata +301
49. Broomfield +336
50. Baca +349
51. Lincoln +395
52. San Miguel +415
53. Prowers +450
54. Larimer +469
55. Pitkin +492
56. Routt +680
57. Summit +849
58. Eagle +1,199
59. Pueblo +1,890
60. Arapahoe +2,322
61. Boulder +4,512
62. Adams +5,400
63. Denver +25,626

Politically Competitive Colorado Counties (Less Then Ten Point Gap) By Bennet Win Margin In Percentage Points, ranked by 2009 population (in parenthesis).

1. Arapahoe +3 (571,598)
2. Jefferson +2 (545,848)
3. Adams +7 (442,971)
4. Larimer +1 (299,284)
5. Broomfield +2 (55,861)
6. Garfield -3 (57,646)
7. La Plata +4 (51,664)
8. Chaffee -2 (17,322)
9. Grand -8 (14,622)
10. Gilpen +6 (5,604)
11. Ouray +5 (4,711)

Disclaimer - 2010 election results not offical, some data is from early returns.