Iowa Redistricting, 2010

[Verily]

Iowa loses a district in 2010, so one of its five congressmen has to go. Poor Tom Latham already represents a marginal district, and it's he who gets the boot. (Although, since Leonard Boswell is a weak incumbent, he might stand a chance at beating Boswell in the new Des Moines district, a D+4 district.)

Haven't calculated the partisanship of the other three districts yet, but they will all be quite safe for their incumbents. I had a slightly better map earlier, but I realized it put Loebsack and Braley in the same district, so I redesigned the map both to keep them in separate districts and to make the new districts more strongly resemble the old districts. King is in green, Loebsack in yellow and Braley in magenta. Boswell and Latham are both in cyan.

Regardless, each district varies from the ideal by less than 0.25%, the sort of precision you can achieve only in a state like Iowa.

Anyway...

[Meeker]

The state does non-partisan, judicial based re-districting, right?

[Verily]

The state does non-partisan, judicial based re-districting, right?

Yes. It would definitely be possible to gerrymander Boswell a much safer district even without county-splitting. (Put Dallas County in King's district and send tendrils out to take in the rural Democratic counties in King's district.) Equally, it would be possible to make Boswell, not Latham, the one who likely loses out.

But I wanted to keep the Des Moines metro together, at least as much as possible, something the current map doesn't achieve. And of course the judiciary would frown on gerrymandering, which I think any serious attempt to save Latham or to make Boswell safer would be.

[minionofmidas]

"judiciary" doesn't describe it. It's a mathematical formula IIRC.

[Verily]

"judiciary" doesn't describe it. It's a mathematical formula IIRC.

You're right, not really judicial. Not quite mathematical, either, though.

http://www.carolinajournal.com/exclusives/display_exclusive.html?id=1317

[Linus Van Pelt]

The way they define "compactness" has the effect of favouring L-shaped districts. (see especially 1, 2 and 4 currently.) This may be less of an issue with only four districts.

[jimrtex]

The way they define "compactness" has the effect of favouring L-shaped districts. (see especially 1, 2 and 4 currently.) This may be less of an issue with only four districts.

Sort of.  The two arms of the L have have equal EW and NS extent (except you can do a hockey stick on the Nebraska border (the EW measurement is from the NW corner of the state to wherever the blade of the stick ends up along the Iowa border.

But you are able to nest L shapes inside each other.   Or sometimes you can have the inside of the two Ls facing each other and pick counties out of the middle.

In the current map, CD1 and CD2 get their compactness from the outer L-shape.  Including counties from the inside of the L, has no effect on their "compactness".

[jimrtex]

The state does non-partisan, judicial based re-districting, right?

They don't permit splitting counties, and districts are required to be compact (in Iowa, this means equal distance between EW and NS).  They also are required to ignore race, politics, and residence of incumbents and current districts.

The districts are actually prepared by a state agency and then approved by the legislature.  After the 2000 redistricting cycle, the legislature voted down the first plan, saying that the deviation was too large (I think one district was off by about 150, which is less than 3/100 of 1%).  I suspect that they just didn't like the districts.

[Holmes]

King is likely to run for governor in 2010... not that it'll prompt his district to change parties, anyway. But still.

[I spent the winter writing songs about getting better]

King is likely to run for governor in 2010... not that it'll prompt his district to change parties, anyway. But still.

Ah, good. It'll be nice to see Culver destroy him.

[muon2]

Regardless, each district varies from the ideal by less than 0.25%, the sort of precision you can achieve only in a state like Iowa.

A true statement. Here's my go at it. My maximum deviation is 0.06% in the Cedar Rapids (NE IA) district. The Des Moines district is usually the hardest to get close and here it is within 0.04%, low by 276 persons.