2020 Redistricting in Pennsylvania

[Mr.Phips]

https://davesredistricting.org/join/222b5cee-1ab5-472a-8ea0-53ea1eb85515

I’m not sure cracking Pittsburgh is a good idea. Those districts are like Biden+11 and Biden+14 and may fall in a wave. Better to have a safe seat and a swing or even R-leaning seat.

That doesn't follow what we've seen in states like Nevada or Oregon.   Democrats seem more interested in maxing their ceiling than their floor.

Don’t forget Illinois.

We also may be seeing the same pattern in MD, NJ, NY if Dems get too greedy.

If Dems are losing Biden + 8 districts, the House is already long gone and so is the Senate of course.

[Tekken_Guy]

https://davesredistricting.org/join/222b5cee-1ab5-472a-8ea0-53ea1eb85515

I’m not sure cracking Pittsburgh is a good idea. Those districts are like Biden+11 and Biden+14 and may fall in a wave. Better to have a safe seat and a swing or even R-leaning seat.

That doesn't follow what we've seen in states like Nevada or Oregon.   Democrats seem more interested in maxing their ceiling than their floor.

Don’t forget Illinois.

We also may be seeing the same pattern in MD, NJ, NY if Dems get too greedy.

If Dems are losing Biden + 8 districts, the House is already long gone and so is the Senate of course.

And that gives them two options:

1. Cede some extra seats to Republicans (i.e. MD-1, NJ-7) to keep their floor as high as possible.
2. Try to raise their ceiling, putting them at risk in an R wave, but knowing they’d hold them in a normal year.

[Oryxslayer]

I am once again asking people to recognize that with both Lamb and Doyle out, there is no longer any need to preserve the ugly current PA-17 Pittsburgh reach-around. Just grab all of the Penn hills region to the west of the city and use the rivers as guidelines for district borders. This near-guarantees a Biden seat, one that could even be more Democratic than the nation if you know what you are aiming for.

Problem is Rs controlling the state legislature would have a collective stroke if Allegheny is drawn too unfavorably to them.

We know the map is either going to the D courts or end up a D-favoring compromise (that'll leave their seats intact and favorable) because the D's used said court as leverage and got a map they liked, so why do they matter? In the latter scenario the R's would care more about securing their own then spending little capital on offense, and the courts in the former clearly wanted to do it in 2018 except Lamb lived in Mt. Lebanon and Doyle had a base in the Swissvale area.

Didn't they draw the 6D/5 swing/7 R map before the special election Lamb won or am I misremembering? Either way as hard as it is to believe 6D/5 swing/6R is D-leaning considering how f---ed the geography of the state is (inb4 "land doesn't vote!" Sorry, we've already decided property >>>> life in this country.) Any more and Rs prolly strip the 5-2 Court of the authority to appoint the tie-breaker to the commission at the first opportunity.

Granted, knowing the um... authoritarian the PAGOP has taken they'll prolly do that anyway whenever they take back the governor's mansion so maybe you're right after all.

The commission is only for legislative lines. Congressional districts are a bill that (likely will not) pass the chamber and the governor's pen, which is why an outside authority will be needed - the same court as last time. And said court last time took steps to correct for the state's geographic lean, which means a mild D-favoring map.

TBH I don't like 'corrective mapping' like this in fair Congressional lines, cause various statewide geographic advantages and the VRA work to cancel out any real political benefit nationwide, so one does not need to correct in a single state. But that is not the rules we play by, and that is not the rules the PA court recognized in 2018.  

[President Punxsutawney Phil]

https://davesredistricting.org/join/222b5cee-1ab5-472a-8ea0-53ea1eb85515

I’m not sure cracking Pittsburgh is a good idea. Those districts are like Biden+11 and Biden+14 and may fall in a wave. Better to have a safe seat and a swing or even R-leaning seat.

That doesn't follow what we've seen in states like Nevada or Oregon.   Democrats seem more interested in maxing their ceiling than their floor.

Don’t forget Illinois.

We also may be seeing the same pattern in MD, NJ, NY if Dems get too greedy.

If Dems are losing Biden + 8 districts, the House is already long gone and so is the Senate of course.

If Biden+11 isn't "safe" then I shudder to imagine what the baseline is for a "safe seat" even is.
Biden+11 and Biden+14 is an unalloyed good for Democrats. 100 times out of a 100.

[President Punxsutawney Phil]

I am once again asking people to recognize that with both Lamb and Doyle out, there is no longer any need to preserve the ugly current PA-17 Pittsburgh reach-around. Just grab all of the Penn hills region to the west of the city and use the rivers as guidelines for district borders. This near-guarantees a Biden seat, one that could even be more Democratic than the nation if you know what you are aiming for.

Problem is Rs controlling the state legislature would have a collective stroke if Allegheny is drawn too unfavorably to them.

We know the map is either going to the D courts or end up a D-favoring compromise (that'll leave their seats intact and favorable) because the D's used said court as leverage and got a map they liked, so why do they matter? In the latter scenario the R's would care more about securing their own then spending little capital on offense, and the courts in the former clearly wanted to do it in 2018 except Lamb lived in Mt. Lebanon and Doyle had a base in the Swissvale area.

Didn't they draw the 6D/5 swing/7 R map before the special election Lamb won or am I misremembering? Either way as hard as it is to believe 6D/5 swing/6R is D-leaning considering how f---ed the geography of the state is (inb4 "land doesn't vote!" Sorry, we've already decided property >>>> life in this country.) Any more and Rs prolly strip the 5-2 Court of the authority to appoint the tie-breaker to the commission at the first opportunity.

Granted, knowing the um... authoritarian the PAGOP has taken they'll prolly do that anyway whenever they take back the governor's mansion so maybe you're right after all.

The commission is only for legislative lines. Congressional districts are a bill that (likely will not) pass the chamber and the governor's pen, which is why an outside authority will be needed - the same court as last time. And said court last time took steps to correct for the state's geographic lean, which means a mild D-favoring map.

TBH I don't like 'corrective mapping' like this in fair Congressional lines, cause various statewide geographic advantages and the VRA work to cancel out any real political benefit nationwide, so one does not need to correct in a single state. But that is not the rules we play by, and that is not the rules the PA court recognized in 2018. 

https://davesredistricting.org/join/e9498594-cb08-4a0a-afe8-96e209594042
This is a quick mock-up of a map trying to follow the rules the PA SC has used.
Did I do a good job?

[politicallefty]

I had a map drawn before the 2018/2020 data was added, so it's good to now see how the map works with the new data.



https://davesredistricting.org/maps#viewmap::242d40ca-00f3-4ca9-80dc-a6a115989228

I had some goals in mind with drawing this map, the first being that it was largely based on the current court-drawn map. Obviously, it keep two districts within Philly, one being majority black (55% VAP) and the other plurality white (41% VAP). I also wanted to draw districts based on the following, so I kept the following counties whole: Bucks, Delaware, Chester, and Lancaster. (There seems to be a non-contiguous precinct from Chester, which is odd.) I also wanted to maintain a Lehigh Valley district, so splitting Lehigh and Northampton was a no-go. Between districts 10, 11, and 13, only Cumberland and York are split. District 12 is a bit of monstrosity, but the alternative made district 9 quite strange looking. I felt this was the better of two options. (As expected, the current PA-09, PA-12, and PA-15 basically collapse into two districts, with the current PA-12 basically being dismantled.) All of Pittsburgh is in 17. However, unlike many maps that put Butler with Beaver and northern Allegheny, I used Westmoreland. From a partisan standpoint, it's very slightly better for Democrats. It also keeps the Erie-based district more compact without going into Central PA.

I will admit that I'm not that fond as to how district 4 turned out. It was the consequence of not hacking up all of the surrounding counties/districts. The thing is that SEPA is growing and that mitigates any significant changes to the area, but the state losing a district does force the area to expand outward. Most maps are not kind to Berks County and this is no exception. The problem is that it's in the middle of a lot of sensible COIs. But apart from district 4, I actually quite like how the map turned out.

Proportionality: 87
Partisan Bias: 62
Competitiveness: 32
Minority Representation: 38
Compactness: 53
Splitting: 65

Among the most competitive districts (using that definition rather loosely):

PA-01: Biden+6.2, Casey+15.4, Wolf+19.8, Clinton+2.3
PA-06: Biden+15.2, Casey+20.0, Wolf+23.8, Clinton+9.3
PA-07: Biden+5.0, Casey+13.9, Wolf+19.4, Clinton+1.3
PA-08: Trump+8.0, Casey+1.1, Wolf+10.0, Trump+13.0
PA-10: Trump+3.6, Casey+1.0, Wolf+9.7, Trump+9.5
PA-16: Biden+1.9, Casey+16.2, Wolf+20.1, Trump+2.6

PRES-2020: 9D-8R
AG-2020: 10D-7R
SEN-2018: 11D-6R
GOV-2018: 11D-6R
PRES-2016: 9R-8D
SEN-2016: 12R-5D (Toomey won PA-06 by 16 votes)
AG-2016: 10D-7R

One other interesting thing I noticed was how well AG Shapiro did in certain traditionally Democratic areas. He outright won the PA-08 I drew and the PA-16 by double digits.

[Boss_Rahm]

I am once again asking people to recognize that with both Lamb and Doyle out, there is no longer any need to preserve the ugly current PA-17 Pittsburgh reach-around. Just grab all of the Penn hills region to the west of the city and use the rivers as guidelines for district borders. This near-guarantees a Biden seat, one that could even be more Democratic than the nation if you know what you are aiming for.

Problem is Rs controlling the state legislature would have a collective stroke if Allegheny is drawn too unfavorably to them.

We know the map is either going to the D courts or end up a D-favoring compromise (that'll leave their seats intact and favorable) because the D's used said court as leverage and got a map they liked, so why do they matter? In the latter scenario the R's would care more about securing their own then spending little capital on offense, and the courts in the former clearly wanted to do it in 2018 except Lamb lived in Mt. Lebanon and Doyle had a base in the Swissvale area.

Didn't they draw the 6D/5 swing/7 R map before the special election Lamb won or am I misremembering? Either way as hard as it is to believe 6D/5 swing/6R is D-leaning considering how f---ed the geography of the state is (inb4 "land doesn't vote!" Sorry, we've already decided property >>>> life in this country.) Any more and Rs prolly strip the 5-2 Court of the authority to appoint the tie-breaker to the commission at the first opportunity.

Granted, knowing the um... authoritarian the PAGOP has taken they'll prolly do that anyway whenever they take back the governor's mansion so maybe you're right after all.

The commission is only for legislative lines. Congressional districts are a bill that (likely will not) pass the chamber and the governor's pen, which is why an outside authority will be needed - the same court as last time. And said court last time took steps to correct for the state's geographic lean, which means a mild D-favoring map.

TBH I don't like 'corrective mapping' like this in fair Congressional lines, cause various statewide geographic advantages and the VRA work to cancel out any real political benefit nationwide, so one does not need to correct in a single state. But that is not the rules we play by, and that is not the rules the PA court recognized in 2018. 

https://davesredistricting.org/join/e9498594-cb08-4a0a-afe8-96e209594042
This is a quick mock-up of a map trying to follow the rules the PA SC has used.
Did I do a good job?

This is perfectly reasonable. Though if a bit of northwest Philly is going in the 4th district I'd expect Roxborough rather than Cedarbrook.

[Born to Slay. Forced to Work.]

a modest proposal - give Philly a republican seat.









yes this is a 5-12 map with a safe republican seat in Philly.

no one tell pagop

https://davesredistricting.org/join/c98f74d5-3dbe-45d5-9c4c-7e33fe32e7e9

[Roll Roons]

I wouldn't be surprised if the Bucks County district gets a bit of Northeast Philly - that's how it was in the 2000s.

[Schiff for Senate]

I think what might happen is an 8-8 map with one competitive seat, or an 8-8 map with one right-leaning district.

[Born to Slay. Forced to Work.]

also just wondering in my map there’s two minority majority seats in Philly, what do y’all think? Is it likely to happen?

[President Punxsutawney Phil]

also just wondering in my map there’s two minority majority seats in Philly, what do y’all think? Is it likely to happen?

I suppose it could quite likely happen. Especially if the map drawers last time are doing it this time as well.

[Oryxslayer]

I think what might happen is an 8-8 map with one competitive seat, or an 8-8 map with one right-leaning district.

This is actually a rather hard outcome given the state's geography and the pre-envisioned communities that base said seats. Any Bucks-anchored seat is going to be marginal, same with any Lehigh Valley seat, and the second Alleghany-based successor seat to PA-17 will be marginal unless Pittsburgh is cracked for some reason.

[EastAnglianLefty]

also just wondering in my map there’s two minority majority seats in Philly, what do y’all think? Is it likely to happen?

It's incredibly simple to draw two Philly seats with a strong black plurality and it would probably have happened decades ago if the machine hadn't been determined to protect Bob Brady.

[Sol]

also just wondering in my map there’s two minority majority seats in Philly, what do y’all think? Is it likely to happen?

It's incredibly simple to draw two Philly seats with a strong black plurality and it would probably have happened decades ago if the machine hadn't been determined to protect Bob Brady.

Yeah on current numbers it's actually pretty easy to draw a straight up Black majority seat and then also a Black plurality seat where Black voters would probably determine the primary outcomes.

Not that that will necessarily happen since Brendan Boyle probably doesn't want it.

[Torie]

I am once again asking people to recognize that with both Lamb and Doyle out, there is no longer any need to preserve the ugly current PA-17 Pittsburgh reach-around. Just grab all of the Penn hills region to the west of the city and use the rivers as guidelines for district borders. This near-guarantees a Biden seat, one that could even be more Democratic than the nation if you know what you are aiming for.

Problem is Rs controlling the state legislature would have a collective stroke if Allegheny is drawn too unfavorably to them.

We know the map is either going to the D courts or end up a D-favoring compromise (that'll leave their seats intact and favorable) because the D's used said court as leverage and got a map they liked, so why do they matter? In the latter scenario the R's would care more about securing their own then spending little capital on offense, and the courts in the former clearly wanted to do it in 2018 except Lamb lived in Mt. Lebanon and Doyle had a base in the Swissvale area.

Didn't they draw the 6D/5 swing/7 R map before the special election Lamb won or am I misremembering? Either way as hard as it is to believe 6D/5 swing/6R is D-leaning considering how f---ed the geography of the state is (inb4 "land doesn't vote!" Sorry, we've already decided property >>>> life in this country.) Any more and Rs prolly strip the 5-2 Court of the authority to appoint the tie-breaker to the commission at the first opportunity.

Granted, knowing the um... authoritarian the PAGOP has taken they'll prolly do that anyway whenever they take back the governor's mansion so maybe you're right after all.

The commission is only for legislative lines. Congressional districts are a bill that (likely will not) pass the chamber and the governor's pen, which is why an outside authority will be needed - the same court as last time. And said court last time took steps to correct for the state's geographic lean, which means a mild D-favoring map.

TBH I don't like 'corrective mapping' like this in fair Congressional lines, cause various statewide geographic advantages and the VRA work to cancel out any real political benefit nationwide, so one does not need to correct in a single state. But that is not the rules we play by, and that is not the rules the PA court recognized in 2018.  

https://davesredistricting.org/join/e9498594-cb08-4a0a-afe8-96e209594042
This is a quick mock-up of a map trying to follow the rules the PA SC has used.
Did I do a good job?

I think you did a good job, and made reasonable choices assuming a Dem friendly but not hackish court that will follow a least change approach in general to the map they drew last time. My main issue is the exchange of real estate between the two CD's in Allegheny County. I understand that makes the Lamb seat more Dem, but aside from that, what is the justification for the exchange that would be based on neutral redistricting metrics?

[President Punxsutawney Phil]

I am once again asking people to recognize that with both Lamb and Doyle out, there is no longer any need to preserve the ugly current PA-17 Pittsburgh reach-around. Just grab all of the Penn hills region to the west of the city and use the rivers as guidelines for district borders. This near-guarantees a Biden seat, one that could even be more Democratic than the nation if you know what you are aiming for.

Problem is Rs controlling the state legislature would have a collective stroke if Allegheny is drawn too unfavorably to them.

We know the map is either going to the D courts or end up a D-favoring compromise (that'll leave their seats intact and favorable) because the D's used said court as leverage and got a map they liked, so why do they matter? In the latter scenario the R's would care more about securing their own then spending little capital on offense, and the courts in the former clearly wanted to do it in 2018 except Lamb lived in Mt. Lebanon and Doyle had a base in the Swissvale area.

Didn't they draw the 6D/5 swing/7 R map before the special election Lamb won or am I misremembering? Either way as hard as it is to believe 6D/5 swing/6R is D-leaning considering how f---ed the geography of the state is (inb4 "land doesn't vote!" Sorry, we've already decided property >>>> life in this country.) Any more and Rs prolly strip the 5-2 Court of the authority to appoint the tie-breaker to the commission at the first opportunity.

Granted, knowing the um... authoritarian the PAGOP has taken they'll prolly do that anyway whenever they take back the governor's mansion so maybe you're right after all.

The commission is only for legislative lines. Congressional districts are a bill that (likely will not) pass the chamber and the governor's pen, which is why an outside authority will be needed - the same court as last time. And said court last time took steps to correct for the state's geographic lean, which means a mild D-favoring map.

TBH I don't like 'corrective mapping' like this in fair Congressional lines, cause various statewide geographic advantages and the VRA work to cancel out any real political benefit nationwide, so one does not need to correct in a single state. But that is not the rules we play by, and that is not the rules the PA court recognized in 2018.  

https://davesredistricting.org/join/e9498594-cb08-4a0a-afe8-96e209594042
This is a quick mock-up of a map trying to follow the rules the PA SC has used.
Did I do a good job?

I think you did a good job, and made reasonable choices assuming a Dem friendly but not hackish court that will follow a least change approach in general to the map they drew last time. My main issue is the exchange of real estate between the two CD's in Allegheny County. I understand that makes the Lamb seat more Dem, but aside from that, what is the justification for the exchange that would be based on neutral redistricting metrics?

The goal was to keep it very competitive. The seat is expanding north into very R territory anyway, so giving it those parts of Allegheny County is a way to maintain its partisanship.
This of course is important for proportionality, which is part of what the court's criteria is. But it's defendable more generally on neutral grounds as well, as helping maintain a competitive district.

[Torie]

I am once again asking people to recognize that with both Lamb and Doyle out, there is no longer any need to preserve the ugly current PA-17 Pittsburgh reach-around. Just grab all of the Penn hills region to the west of the city and use the rivers as guidelines for district borders. This near-guarantees a Biden seat, one that could even be more Democratic than the nation if you know what you are aiming for.

Problem is Rs controlling the state legislature would have a collective stroke if Allegheny is drawn too unfavorably to them.

We know the map is either going to the D courts or end up a D-favoring compromise (that'll leave their seats intact and favorable) because the D's used said court as leverage and got a map they liked, so why do they matter? In the latter scenario the R's would care more about securing their own then spending little capital on offense, and the courts in the former clearly wanted to do it in 2018 except Lamb lived in Mt. Lebanon and Doyle had a base in the Swissvale area.

Didn't they draw the 6D/5 swing/7 R map before the special election Lamb won or am I misremembering? Either way as hard as it is to believe 6D/5 swing/6R is D-leaning considering how f---ed the geography of the state is (inb4 "land doesn't vote!" Sorry, we've already decided property >>>> life in this country.) Any more and Rs prolly strip the 5-2 Court of the authority to appoint the tie-breaker to the commission at the first opportunity.

Granted, knowing the um... authoritarian the PAGOP has taken they'll prolly do that anyway whenever they take back the governor's mansion so maybe you're right after all.

The commission is only for legislative lines. Congressional districts are a bill that (likely will not) pass the chamber and the governor's pen, which is why an outside authority will be needed - the same court as last time. And said court last time took steps to correct for the state's geographic lean, which means a mild D-favoring map.

TBH I don't like 'corrective mapping' like this in fair Congressional lines, cause various statewide geographic advantages and the VRA work to cancel out any real political benefit nationwide, so one does not need to correct in a single state. But that is not the rules we play by, and that is not the rules the PA court recognized in 2018.  

https://davesredistricting.org/join/e9498594-cb08-4a0a-afe8-96e209594042
This is a quick mock-up of a map trying to follow the rules the PA SC has used.
Did I do a good job?

I think you did a good job, and made reasonable choices assuming a Dem friendly but not hackish court that will follow a least change approach in general to the map they drew last time. My main issue is the exchange of real estate between the two CD's in Allegheny County. I understand that makes the Lamb seat more Dem, but aside from that, what is the justification for the exchange that would be based on neutral redistricting metrics?

The goal was to keep it very competitive. The seat is expanding north into very R territory anyway, so giving it those parts of Allegheny County is a way to maintain its partisanship.
This of course is important for proportionality, which is part of what the court's criteria is. But it's defendable more generally on neutral grounds as well, as helping maintain a competitive district.

Are you sure that making seats competitive or proportionality was explicitly embraced by the court? In addition, the existing map has an ugly chop of the black community, creating an erose line to boot. What I did in the map below, is have the Pittsburgh seat take the balance of the two chopped cities, and then smooth out the line south of the river, and then take one small city in the other indented area to the south, and then chop a small city by about 300 people. The Lamb CD is still quite competitive. I would be surprised if the court goes for erosity and chopping the black community to make the seat a couple of points more Dem.

https://davesredistricting.org/join/0aba5052-7f1f-4d91-a9d7-399abe34d796

[Devils30]

https://davesredistricting.org/join/222b5cee-1ab5-472a-8ea0-53ea1eb85515

I’m not sure cracking Pittsburgh is a good idea. Those districts are like Biden+11 and Biden+14 and may fall in a wave. Better to have a safe seat and a swing or even R-leaning seat.

That doesn't follow what we've seen in states like Nevada or Oregon.   Democrats seem more interested in maxing their ceiling than their floor.

Don’t forget Illinois.

We also may be seeing the same pattern in MD, NJ, NY if Dems get too greedy.

If Dems are losing Biden + 8 districts, the House is already long gone and so is the Senate of course.

And that gives them two options:

1. Cede some extra seats to Republicans (i.e. MD-1, NJ-7) to keep their floor as high as possible.
2. Try to raise their ceiling, putting them at risk in an R wave, but knowing they’d hold them in a normal year.

Dems are stupid to cede seats like MD-1, NJ-7...its about holding them in a 50-50 year, don't worry about a wave. Be prepared in the event Roe gets overturned for things to backfire on the GOP just in case.

[President Punxsutawney Phil]

I am once again asking people to recognize that with both Lamb and Doyle out, there is no longer any need to preserve the ugly current PA-17 Pittsburgh reach-around. Just grab all of the Penn hills region to the west of the city and use the rivers as guidelines for district borders. This near-guarantees a Biden seat, one that could even be more Democratic than the nation if you know what you are aiming for.

Problem is Rs controlling the state legislature would have a collective stroke if Allegheny is drawn too unfavorably to them.

We know the map is either going to the D courts or end up a D-favoring compromise (that'll leave their seats intact and favorable) because the D's used said court as leverage and got a map they liked, so why do they matter? In the latter scenario the R's would care more about securing their own then spending little capital on offense, and the courts in the former clearly wanted to do it in 2018 except Lamb lived in Mt. Lebanon and Doyle had a base in the Swissvale area.

Didn't they draw the 6D/5 swing/7 R map before the special election Lamb won or am I misremembering? Either way as hard as it is to believe 6D/5 swing/6R is D-leaning considering how f---ed the geography of the state is (inb4 "land doesn't vote!" Sorry, we've already decided property >>>> life in this country.) Any more and Rs prolly strip the 5-2 Court of the authority to appoint the tie-breaker to the commission at the first opportunity.

Granted, knowing the um... authoritarian the PAGOP has taken they'll prolly do that anyway whenever they take back the governor's mansion so maybe you're right after all.

The commission is only for legislative lines. Congressional districts are a bill that (likely will not) pass the chamber and the governor's pen, which is why an outside authority will be needed - the same court as last time. And said court last time took steps to correct for the state's geographic lean, which means a mild D-favoring map.

TBH I don't like 'corrective mapping' like this in fair Congressional lines, cause various statewide geographic advantages and the VRA work to cancel out any real political benefit nationwide, so one does not need to correct in a single state. But that is not the rules we play by, and that is not the rules the PA court recognized in 2018.  

https://davesredistricting.org/join/e9498594-cb08-4a0a-afe8-96e209594042
This is a quick mock-up of a map trying to follow the rules the PA SC has used.
Did I do a good job?

I think you did a good job, and made reasonable choices assuming a Dem friendly but not hackish court that will follow a least change approach in general to the map they drew last time. My main issue is the exchange of real estate between the two CD's in Allegheny County. I understand that makes the Lamb seat more Dem, but aside from that, what is the justification for the exchange that would be based on neutral redistricting metrics?

The goal was to keep it very competitive. The seat is expanding north into very R territory anyway, so giving it those parts of Allegheny County is a way to maintain its partisanship.
This of course is important for proportionality, which is part of what the court's criteria is. But it's defendable more generally on neutral grounds as well, as helping maintain a competitive district.

Are you sure that making seats competitive or proportionality was explicitly embraced by the court? In addition, the existing map has an ugly chop of the black community, creating an erose line to boot. What I did in the map below, is have the Pittsburgh seat take the balance of the two chopped cities, and then smooth out the line south of the river, and then take one small city in the other indented area to the south, and then chop a small city by about 300 people. The Lamb CD is still quite competitive. I would be surprised if the court goes for erosity and chopping the black community to make the seat a couple of points more Dem.

https://davesredistricting.org/join/0aba5052-7f1f-4d91-a9d7-399abe34d796

Proportionality was definitely a factor, albeit only one factor, in how the PA SC drew the lines last time (just look at how the Bucks County CD was drawn).
It'd be surprising if a court were to place having as much of the blacks of Allegheny County in one seat above all considerations either. The existing court map has Penn Hills (37% AA) in the northern Allegheny seat. Let's not forget this is a county that is only 13% black. If it were, say, double that, then there might be a case. In any case, to the extent that it would be even relevant, it's probably likely that if given a choice, AAs in the county would prefer to be divided for sake of improving D chances in the swing district, as opposed to packing Ds into one safe seat.

[Torie]

I am once again asking people to recognize that with both Lamb and Doyle out, there is no longer any need to preserve the ugly current PA-17 Pittsburgh reach-around. Just grab all of the Penn hills region to the west of the city and use the rivers as guidelines for district borders. This near-guarantees a Biden seat, one that could even be more Democratic than the nation if you know what you are aiming for.

Problem is Rs controlling the state legislature would have a collective stroke if Allegheny is drawn too unfavorably to them.

We know the map is either going to the D courts or end up a D-favoring compromise (that'll leave their seats intact and favorable) because the D's used said court as leverage and got a map they liked, so why do they matter? In the latter scenario the R's would care more about securing their own then spending little capital on offense, and the courts in the former clearly wanted to do it in 2018 except Lamb lived in Mt. Lebanon and Doyle had a base in the Swissvale area.

Didn't they draw the 6D/5 swing/7 R map before the special election Lamb won or am I misremembering? Either way as hard as it is to believe 6D/5 swing/6R is D-leaning considering how f---ed the geography of the state is (inb4 "land doesn't vote!" Sorry, we've already decided property >>>> life in this country.) Any more and Rs prolly strip the 5-2 Court of the authority to appoint the tie-breaker to the commission at the first opportunity.

Granted, knowing the um... authoritarian the PAGOP has taken they'll prolly do that anyway whenever they take back the governor's mansion so maybe you're right after all.

The commission is only for legislative lines. Congressional districts are a bill that (likely will not) pass the chamber and the governor's pen, which is why an outside authority will be needed - the same court as last time. And said court last time took steps to correct for the state's geographic lean, which means a mild D-favoring map.

TBH I don't like 'corrective mapping' like this in fair Congressional lines, cause various statewide geographic advantages and the VRA work to cancel out any real political benefit nationwide, so one does not need to correct in a single state. But that is not the rules we play by, and that is not the rules the PA court recognized in 2018.  

https://davesredistricting.org/join/e9498594-cb08-4a0a-afe8-96e209594042
This is a quick mock-up of a map trying to follow the rules the PA SC has used.
Did I do a good job?

I think you did a good job, and made reasonable choices assuming a Dem friendly but not hackish court that will follow a least change approach in general to the map they drew last time. My main issue is the exchange of real estate between the two CD's in Allegheny County. I understand that makes the Lamb seat more Dem, but aside from that, what is the justification for the exchange that would be based on neutral redistricting metrics?

The goal was to keep it very competitive. The seat is expanding north into very R territory anyway, so giving it those parts of Allegheny County is a way to maintain its partisanship.
This of course is important for proportionality, which is part of what the court's criteria is. But it's defendable more generally on neutral grounds as well, as helping maintain a competitive district.

Are you sure that making seats competitive or proportionality was explicitly embraced by the court? In addition, the existing map has an ugly chop of the black community, creating an erose line to boot. What I did in the map below, is have the Pittsburgh seat take the balance of the two chopped cities, and then smooth out the line south of the river, and then take one small city in the other indented area to the south, and then chop a small city by about 300 people. The Lamb CD is still quite competitive. I would be surprised if the court goes for erosity and chopping the black community to make the seat a couple of points more Dem.

https://davesredistricting.org/join/0aba5052-7f1f-4d91-a9d7-399abe34d796

Proportionality was definitely a factor, albeit only one factor, in how the PA SC drew the lines last time (just look at how the Bucks County CD was drawn).
It'd be surprising if a court were to place having as much of the blacks of Allegheny County in one seat above all considerations either. The existing court map has Penn Hills (37% AA) in the northern Allegheny seat. Let's not forget this is a county that is only 13% black. If it were, say, double that, then there might be a case. In any case, to the extent that it would be even relevant, it's probably likely that if given a choice, AAs in the county would prefer to be divided for sake of improving D chances in the swing district, as opposed to packing Ds into one safe seat.

Below is a link to the court decision last time. The court focused on minimizing splits and compactness. They failed to explain why two municipalities were chopped in Allegheny County rather than just one, and just said in general all the competing plans had more splits. Nor did they comment about the seeming unnecessary erosity in the county. The decision was quite conclusory. The litigants would be wise to channel its metric and point out where it seemed not to be followed. There was no mention of proportionality or competitiveness.

https://www.brennancenter.org/our-work/court-cases/league-women-voters-pennsylvania-v-commonwealth-pennsylvania

[Gass3268]

https://twitter.com/RedistrictNet/status/1468653648372711433?s=20

[President Punxsutawney Phil]

That map looks mildly GOP-friendly.

[lfromnj]

That map looks mildly GOP-friendly.

Its the GOP proposal.

[Gass3268]

https://twitter.com/JMilesColeman/status/1468656541624643586?s=20