Redistricting for the US House and the US state legislatures

[lpetrich]

Here are some examples with one such algorithm:
2020 Redistricting Results
2010 Redistricting Results
BDistricting
at
bolson.org

Source code is at
GitHub - brianolson/redistricter: open source impartial algorithmic redistricting

 

[lpetrich]

Brian Olson's BDistricting software uses great-circle distance, though it requires calculating trigonometric functions.

\( \cos d = \sin b_1 \sin b_2 + \cos b_1 \cos b_2 \cos (l_2 - l_1) \)

angular distance d from latitudes b and longitudes l for points 1 and 2. This formula has accuracy problems for close points, so the "haversine formula" is often used:

\( \text{hav}\, d = \text{hav} (b2 - b1) + \cos b_1 \cos b_2 \text{hav} (l_2 - l_1) \)

where the haversine function is

\( \text{hav}\, a = (1 - \cos a)/2 = \sin^2 (a/2) \)

So one needs 4 trig functions, 1 square root, and 1 inverse-trig function per evaluation.

One can eliminate 2 of the trig-function calculations by precalculating cosines of latitudes, and one can eliminate all of them by precalculating direction vectors and then using vector algebra. One still needs an inverse-trig function for calculating the distance, though one can use a Padé-approximant rational-function approximation for it. One will still need a square root, however.

For unit vectors n1 and n2, d is

\( \cos d = {\vec n_1} \cdot {\vec n_2} \)

\( \sin (d/2) = \frac12 |\vec n_1 - \vec n_2| \)

The vectors themselves are

\( \vec n = \{ \cos b \cos l , \cos b \sin l , \sin b \} \)

requiring only 4 trig functions each, though one can use trig identities and square roots to get it down to 2 trig functions and 2 square roots.

 

[Jimmy Higgins]

Yeah, Gerrymandering is crap. For Republicans to complain about it is the utter peak of hypocrisy.

For this, we actually do need a Constitutional Amendment, but how to require redistricting without Gerrymandering probably isn't the easiest to put into words.

Base your districts solely upon population i.e N voters per district +-%N variance.
Do not use skin colour, language, past voting, future voting intentions etc. as the basis.
Surely you septics could manage that?
Easier to do and less prone to challenges that your current dog's breakfast

While it technically could be done, to be done everywhere would require a Constitutional Amendment (read it ain't never happening!).

I keep reading on these threads that Democrats constantly ask for a better (more consistent, less interference etc.) system of electorate generation. So why does not one of the states that is controlled by Democrats actually try a purely numeric scheme?

Up to this year, some Democrat controlled states have non-partisan boards manage redistricting, like California and Colorado., and when I say like, I mean, that is about it. If California was like Texas, California would have many more Democrats. This year, any sense of non-partisan redistricting was tossed out the window as the GOP aggressively weeds out Democrat seats in states like Ohio and the Dems are playing the game all out too, except where not allowed by law.

They could perform a competitive, controlled test against the other versions to see who is the fairest in the land.
Or is that just too hard?

That is what should be done, but our democracy really appears to be past the point of no return for dissolution of two party rule. It'd be hard for the Dems to play by fairer rules, only to be usurped by the GOP. We see this in the House of Representatives, where the Democrats can win by a notably larger percentage of the popular vote, but manage to get fewer seat majorities.

So the Dems are across the board gerrymandering like the GOP has, though the GOP has really stretched it in places like Ohio, where they are trying to make Ohio look like Kansas. Heck, the GOP floated gerrymandering the electoral college by splitting purple state EV's by candidate's percentage of vote, making it nearly impossible for the Dems to win. But at least that plan failed.

 

[lpetrich]

Back to 538.
What Redistricting Looks Like In Every State | FiveThirtyEight

Minnesota now has a map. Its borders are not much different, and its partisan composition almost identical.

No other updates in the last few days, though Rhode Island's map looks ready to go. Just like Hawaii and Connecticut for some months.

 

[Jimmy Higgins]

Ohio continues to be a clusterfuck. The commission isn't even going to bother to try and care. The Supreme Court said no more deadlines, so it is hard to tell what the next step is.

I like how Gov. Dewine agreed the process must move forward, but that the current heavily gerrymandered map isn't gerrymandered enough... I'm sorry, they said "The biggest hurdle remains that Ohio’s political geography does not match the proportionality of recent statewide votes."

That sounds right, but what they actually mean is that the GOP having only 75% of the US House seats isn't fair.

 

[Tigers!]

Ohio continues to be a clusterfuck. The commission isn't even going to bother to try and care. The Supreme Court said no more deadlines, so it is hard to tell what the next step is.

I like how Gov. Dewine agreed the process must move forward, but that the current heavily gerrymandered map isn't gerrymandered enough... I'm sorry, they said "The biggest hurdle remains that Ohio’s political geography does not match the proportionality of recent statewide votes."

That sounds right, but what they actually mean is that the GOP having only 75% of the US House seats isn't fair.

Unlike you stop allowing past voting patterns to affect the future composition of electorates you will just go round and round.

 

[lpetrich]

Florida continues to be deadlocked.

Who	D++	D+	D	0	R	R+	R++
	D>=15	D>=5	D>=1	0 (even)	R>=1	R>=5	R>=15
Old Map	5	3	3	0	2	3	11
FL Senate	6	2	3	1	2	2	12
FL House	6	2	1	1	3	3	12
FL Gov 1	6	2	1	0	2	4	13
FL Gov 2	6	2	0	0	2	6	12

Governor Ron DeSantis, of course. DeSatan, DeathSentence, ...

For a more fine-grained comparison, I should collect all the partisanship scores and then compare their distributions.

 

[Tigers!]

It would be very nice for you if you did not have to do all this mucking around. Think of the hours you would save.

Your work is appreciated even if I think you septics are very stupid in some things.

 

[lpetrich]

Rhode Island now has a map. It is nearly identical to the previous map, and it has a nearly identical partisan composition.

RI also seems to be the last of the states without a lot of controversy over its maps.

Most recent updates at 538: WI last year Dec 16 - NH Jan 5 - MO, OH, PA Feb 8 - LA Feb 10 - FL Feb 15 - NC Feb 18

Of these maps, MO's map seems the most likely to be signed into law by the governor without much further controversy. LA's governor might veto the legislature's map, and NH has no updates more recent than the State House passing the map and sending it to the State Senate. Of the remaining five states, in FL, PA, and WI, the governor and the legislature are at loggerheads, and in NC, OH, PA, and WI, the courts are involved.

New Hampshire redistricting update: Senate approves maps - for the state legislature. Nothing on the Congressional map.

The battle to control Congress comes to N.H., sparking charges of gerrymandering | WBUR News

 

[TV and credit cards]

Ohio Governor Goes to Prison for Contempt of Court.

Maybe. I figured all along they would just run out the clock. But what now? Sonny boy is on the court but he is just one vote. For now.

The GOP commission members said during the meeting that they could not find a way to draw maps that complied with all the redistricting provisions of the constitution, while also complying with the rules the supreme court had given in their majority opinion invalidating the previous maps. Mainly, the GOP said they couldn’t hit the target of 54-46 partisan breakdown asked for by the court justices, a number based on statewide voter preferences over the last 10 years.

While my first thought was, “can’t or won’t?”, I think perhaps it is “can’t”. That there may be some psychological disorder that is creating such distress among the Republican members of the ORC that they actually can’t create a map that satisfies the constitutional requirement and the Supreme Court. At least that’d be my argument to fight the contempt charge.

 

[Jimmy Higgins]

Ohio Governor Goes to Prison for Contempt of Court.

Maybe. I figured all along they would just run out the clock. But what now? Sonny boy is on the court but he is just one vote. For now.

The GOP commission members said during the meeting that they could not find a way to draw maps that complied with all the redistricting provisions of the constitution, while also complying with the rules the supreme court had given in their majority opinion invalidating the previous maps. Mainly, the GOP said they couldn’t hit the target of 54-46 partisan breakdown asked for by the court justices, a number based on statewide voter preferences over the last 10 years.

While my first thought was, “can’t or won’t?”, I think perhaps it is “can’t”. That there may be some psychological disorder that is creating such distress among the Republican members of the ORC that they actually can’t create a map that satisfies the constitutional requirement and the Supreme Court. At least that’d be my argument to fight the contempt charge.

They refuse to do it. They are creating this BS conflict that the Constitution requires one thing and the Supreme Court is requiring another. That is a lie.

They have taken our state hostage. And why not. What can the Supreme Court do? The GOP will seize every square mile of territory they can to make Ohio appear to be redder than Alabama.

 

[lpetrich]

North Carolina and Pennsylvania now have maps.

North Carolina's one was approved by a 3-judge redistricting panel that threw out a Republican-proposed map as too biased toward that party. This map adds 1 Democratic and 1 competitive seat and subtracts 1 Republican seat, giving 6 D's, 7 R's, and 1 C (competitive). But the Republicans may appeal this one to the state's Supreme Court.

Pennsylvania's one was approved by the state's Supreme Court, and it subtracts 1 R seat, giving 6 D, 8 R, 3 C.

That leaves 6 states without new maps: FL, LA, MO, NH, OH, WI. Of these, the only one with an update in the last few days is LA. Late last week, the legislature passed a map with 5 R's and 1 D. Gov. John Bel Edwards wants a map that is 4 R 2 D, and he is thinking of vetoing that map.

What Redistricting Looks Like In Every State | FiveThirtyEight

 

[Jimmy Higgins]

GOP in Ohio asked for more time to avoid contempt charges from the Ohio Supreme Court, when the GOP decided to say 'screw it'. Of course, their hands are tied, they can't both gerrymander a map and follow the Constitution and the Supreme Court.

 

[Loren Pechtel]

Ohio Governor Goes to Prison for Contempt of Court.

Maybe. I figured all along they would just run out the clock. But what now? Sonny boy is on the court but he is just one vote. For now.

The GOP commission members said during the meeting that they could not find a way to draw maps that complied with all the redistricting provisions of the constitution, while also complying with the rules the supreme court had given in their majority opinion invalidating the previous maps. Mainly, the GOP said they couldn’t hit the target of 54-46 partisan breakdown asked for by the court justices, a number based on statewide voter preferences over the last 10 years.

While my first thought was, “can’t or won’t?”, I think perhaps it is “can’t”. That there may be some psychological disorder that is creating such distress among the Republican members of the ORC that they actually can’t create a map that satisfies the constitutional requirement and the Supreme Court. At least that’d be my argument to fight the contempt charge.

You missed a key paragraph in the article:

The groups also asked for justification for the commission’s lack of action on any sort of map, despite being presented with a map by the Democratic House and Senate caucuses, which they shot down along party lines on the day of the deadline.

They are saying they can't do something that has been shown to be possible.

 

[Jimmy Higgins]

Ohio Governor Goes to Prison for Contempt of Court.

Maybe. I figured all along they would just run out the clock. But what now? Sonny boy is on the court but he is just one vote. For now.

The GOP commission members said during the meeting that they could not find a way to draw maps that complied with all the redistricting provisions of the constitution, while also complying with the rules the supreme court had given in their majority opinion invalidating the previous maps. Mainly, the GOP said they couldn’t hit the target of 54-46 partisan breakdown asked for by the court justices, a number based on statewide voter preferences over the last 10 years.

While my first thought was, “can’t or won’t?”, I think perhaps it is “can’t”. That there may be some psychological disorder that is creating such distress among the Republican members of the ORC that they actually can’t create a map that satisfies the constitutional requirement and the Supreme Court. At least that’d be my argument to fight the contempt charge.

You missed a key paragraph in the article:

The groups also asked for justification for the commission’s lack of action on any sort of map, despite being presented with a map by the Democratic House and Senate caucuses, which they shot down along party lines on the day of the deadline.

They are saying they can't do something that has been shown to be possible.

It was explicitly clear that it was possible. Heck, they could just use the same darn that exists for the current districts (and get away with it). But no, they want to make it sound impossible, as if the Supreme Court is comprised of idiots. Partisans, yes. Idiots, no.

The GOP went down the road of Mega-Gerrymandering, and slicing away two Democrat seats... when we already only had 4 in a state with 16, that is still purple-ish. And then wave their arms saying 'no one could make a map in this state'.

 

[Jarhyn]

Ohio Governor Goes to Prison for Contempt of Court.

Maybe. I figured all along they would just run out the clock. But what now? Sonny boy is on the court but he is just one vote. For now.

The GOP commission members said during the meeting that they could not find a way to draw maps that complied with all the redistricting provisions of the constitution, while also complying with the rules the supreme court had given in their majority opinion invalidating the previous maps. Mainly, the GOP said they couldn’t hit the target of 54-46 partisan breakdown asked for by the court justices, a number based on statewide voter preferences over the last 10 years.

While my first thought was, “can’t or won’t?”, I think perhaps it is “can’t”. That there may be some psychological disorder that is creating such distress among the Republican members of the ORC that they actually can’t create a map that satisfies the constitutional requirement and the Supreme Court. At least that’d be my argument to fight the contempt charge.

But then they fail at the competency of being on the commission at all.

 

[Rhea]

Now that we’ve had some primaries
(Article about the outcomes). https://electoral-vote.com/evp2022/Senate/Maps/Mar02.html#item-3

Some of those redistricting efforts show some clarity in Texas:

The lessons here are: (1) It was a pretty good night for progressive Democrats, (2) it's great to be an incumbent, and (3) it's not so great to be under criminal investigation or indictment. The next primaries are on May 3 in Ohio and Indiana. (Z)

There’s some commentary on PA, too.

 

[lpetrich]

Ohio now has a map.

It's almost as gerrymandered as the previous map, with 2 D, 11 R, 2 C. Down 1 D, 1 R and up 1 C from the previous map (Ohio lost a seat).

This is much like what Republicans had proposed, though one Republican made one of the competitive seats more R: 2 D, 12 R, 1 C. For their part, Democrats proposed maps like 4 D, 8 R, 3 C.

So 39 states now have new maps, and with 6 one-district states, that leaves 5 states without new maps.

The Florida legislature and Gov. DeSantis are still at loggerheads, and there isn't much new from the other four states, LA, MO, NH, and WI.

 

[Jimmy Higgins]

Jebus!

My district was the main change, went from leaning GOP to likely Dem... which is currently definitely Dem. The purple area from my old district now joins with the red district up on the NE corner of the state. And they gerrymandered what was to be my district up north and disenfranchised much of Cuyahoga County. District 9 is nuts because they are drowning out the voters in Lucas County (Toledo).

I had no idea it was possible to pass redistricting reform and to get a more gerrymandered map. 12 of 16 seats seemed pretty damn gerrymandered already. Ohio has had its coup.

 

[lpetrich]

Wisconsin now has a map. The state's Supreme Court went with Gov. Evers, a Democrat, rather than with the state legislature, which is Republican-dominated. The court accepted his map for the US House and for the two chambers of the state legislature. He decided on a "least change" approach, meaning that his maps favor the Republicans, but not as much as the Republicans want. Also meaning that he didn't try to gerrymander them in favor of the Democrats.

What Redistricting Looks Like In Every State | FiveThirtyEight
Home Page - All About Redistricting

This means that there are only four states without new maps: FL, LA, MO, and NH. Of these states, NH was last updated Jan 5, MO Feb 8, LA Feb 22, and FL Mar 4. In FL, the legislature has agreed on a two-map approach, a primary one, and a secondary one in case the courts strike down the primary one. But Gov. DeSantis isn't happy with either map, and the courts may get involved.

Having new maps does not mean the end of litigation; some states with new maps have litigation over them: GA, KS, KY, MD, MI, NC, NJ, NM, NV, NY, PA, SC, TX, WI.