State Partisan Control, 2005-2019

[Doimper]

Insane that PA Repubs are still in control of the legislature, even after Casey and Wolf's landslides.

Holding the legislature despite losing the popular vote by 10 points is the American Way™

At least their grubby hands were pried off the Congressional map.

[Antonio the Sixth]

An interesting measure might be district errosity over time. For example, is this really partisanship at play? Or did perhaps the 2010 cycle produce a bunch of Pub and Dem local maps that push states towards one unified type of government. I suspect the facts might be somewhere in between, after one examines just a handful of legislatures.

I mean, yeah, gerrymandering definitely played a role, and it's pretty likely that at least a few more States (out of, say, WI, MI, PA, NC) would have split legislatures if it weren't for it. Still, gerrymandering has been a thing for several decades, but the rise of unified government at the State level has been a pretty recent development. Besides, this explanation kind of begs the question, since enacting a gerrymander first requires united government.

[Oryxslayer]

An interesting measure might be district errosity over time. For example, is this really partisanship at play? Or did perhaps the 2010 cycle produce a bunch of Pub and Dem local maps that push states towards one unified type of government. I suspect the facts might be somewhere in between, after one examines just a handful of legislatures.

I mean, yeah, gerrymandering definitely played a role, and it's pretty likely that at least a few more States (out of, say, WI, MI, PA, NC) would have split legislatures if it weren't for it. Still, gerrymandering has been a thing for several decades, but the rise of unified government at the State level has been a pretty recent development. Besides, this explanation kind of begs the question, since enacting a gerrymander first requires united government.

I guess I should have been more clear,  I mean the rise of deep data gerrymanders, made possible by modern computer programs with electoral data and tools going back centuries. The kind of software the allows one to draw a Republican district that resembles nothing except Donald Kicking Goofy from two democratic counties. And it really doesn't need to be unified control, as shown by NY where the state house map was gerryed to produce a dem supermajority, and state senate map gerryed to produce a republican majority. In this case, the gerry wanted to produce divided govt. If we accept that the deep-data gerry is new, then there is a theory that state reps could win a majority under 'fairer' gerryed lines (whatever that means) drawn by the opposition because they lacked deep data, and then draw deep data lines to reinforce their new majority. But beyond that yes, it does lead to a chicken and egg scenario which is why I suspect Gerry's are working alongside other factors like the polarization demonstrated above and decline of split ticketing.  

[Antonio the Sixth]

An interesting measure might be district errosity over time. For example, is this really partisanship at play? Or did perhaps the 2010 cycle produce a bunch of Pub and Dem local maps that push states towards one unified type of government. I suspect the facts might be somewhere in between, after one examines just a handful of legislatures.

I mean, yeah, gerrymandering definitely played a role, and it's pretty likely that at least a few more States (out of, say, WI, MI, PA, NC) would have split legislatures if it weren't for it. Still, gerrymandering has been a thing for several decades, but the rise of unified government at the State level has been a pretty recent development. Besides, this explanation kind of begs the question, since enacting a gerrymander first requires united government.

I guess I should have been more clear,  I mean the rise of deep data gerrymanders, made possible by modern computer programs with electoral data and tools going back centuries. The kind of software the allows one to draw a Republican district that resembles nothing except Donald Kicking Goofy from two democratic counties. And it really doesn't need to be unified control, as shown by NY where the state house map was gerryed to produce a dem supermajority, and state senate map gerryed to produce a republican majority. In this case, the gerry wanted to produce divided govt. If we accept that the deep-data gerry is new, then there is a theory that state reps could win a majority under 'fairer' gerryed lines (whatever that means) drawn by the opposition because they lacked deep data, and then draw deep data lines to reinforce their new majority. But beyond that yes, it does lead to a chicken and egg scenario which is why I suspect Gerry's are working alongside other factors like the polarization demonstrated above and decline of split ticketing. 

We're not really in disagreement then. Still, even if gerrymandering is completely eliminated, I doubt you'll see split legislatures in states like Oklahoma, Tennessee or Alabama again anytime soon.

[smoltchanov]

An interesting measure might be district errosity over time. For example, is this really partisanship at play? Or did perhaps the 2010 cycle produce a bunch of Pub and Dem local maps that push states towards one unified type of government. I suspect the facts might be somewhere in between, after one examines just a handful of legislatures.

I mean, yeah, gerrymandering definitely played a role, and it's pretty likely that at least a few more States (out of, say, WI, MI, PA, NC) would have split legislatures if it weren't for it. Still, gerrymandering has been a thing for several decades, but the rise of unified government at the State level has been a pretty recent development. Besides, this explanation kind of begs the question, since enacting a gerrymander first requires united government.

I guess I should have been more clear,  I mean the rise of deep data gerrymanders, made possible by modern computer programs with electoral data and tools going back centuries. The kind of software the allows one to draw a Republican district that resembles nothing except Donald Kicking Goofy from two democratic counties. And it really doesn't need to be unified control, as shown by NY where the state house map was gerryed to produce a dem supermajority, and state senate map gerryed to produce a republican majority. In this case, the gerry wanted to produce divided govt. If we accept that the deep-data gerry is new, then there is a theory that state reps could win a majority under 'fairer' gerryed lines (whatever that means) drawn by the opposition because they lacked deep data, and then draw deep data lines to reinforce their new majority. But beyond that yes, it does lead to a chicken and egg scenario which is why I suspect Gerry's are working alongside other factors like the polarization demonstrated above and decline of split ticketing. 

We're not really in disagreement then. Still, even if gerrymandering is completely eliminated, I doubt you'll see split legislatures in states like Oklahoma, Tennessee or Alabama again anytime soon.

The same is true for California, Illinois, Massachusetts or Vermont too. In too many states overall results became too predictable, and thus - elections are openly boring...

[Epaminondas]

Now you can turn Virginia red on that great map of yours.

(Why not use Atlas colours?)

[Antonio the Sixth]

I was going to wait until January when the new state governments actually take office, but fair enough! Here it is:


Overall State Control, 2020

Democratic Trifecta: 15 States, 37.3%
Dem. Legislature, Rep. Governor: 4 States, 4.6%
Dem. Governor, Split Legislature: 1 State, 1.7%
Rep. Legislature, Dem. Governor: 8 States, 16.4%
Republican Trifecta: 22 States, 40.0%

There's now almost (but not quite...) as many people living under Democratic as Republican trifectas. Total share of people under a trifecta also rose, since VA is bigger than KY. Still Republican have an edge in raw state numbers.



Democrats break a new records in the share of people they hold a trifecta over, although the share of people under a Democratic legislature is only back to where it was after the 2006 cycle. Meanwhile, the share of people under full Republican control continues to inch down but is still higher than at any point before their 2010 sweep. And the share of people under a Republican legislature is higher than at any point before the 2014 sweep.


I don't have time to look through all the current state legislative breakdowns (and they might still change between now and January) but sometime early next year I will also be updating the SLRI figures.