on representation, redistricting, and "gerrymandering" (with 2024 election data)

"Gerrymandering" is always a possibility in a republic, but sometimes the topic moves to the front burner. We're in one of those moments now. Last month, the Texas GOP stirred the pot with its efforts to "redistrict" and Democrat leaders in a few states responded with angry rhetoric and promises to retaliate.  

Let’s start by defining and explaining the relevant terms. “Redistricting” is the practice of redrawing the geographical lines that define a political district, given changes in national and state populations. These changes are measured at the beginning of every decade through the work of the U.S. Census Bureau.  

Consider the 435 seats in the U.S. House of Representatives. If a state's population grows/shrinks enough with respect to the national population, a state will gain/lose a seat (or more). In such cases, a state must redraw its district lines, accommodating more/fewer seats for the same geographical area. But even if the number of seats remains the same, lines are likely redrawn as population shifts within the state—from births and deaths, immigration and emigration.  

Six states have one district, so they can't redistrict. In 25 of the more populous states, these lines are redrawn by the state legislature (often approved by the governor). In the other 19 multi-district states, an independent or bipartisan group does the work in order to limit political shenanigans. And of course, the process can always be regulated by the judiciary.  

“Gerrymandering” is the practice of drawing these lines for political purposes. (The word was created by merging “salamander” with the name of the Massachusetts governor who did this in 1812, Elbridge Gerry.) But there are some inherent tensions in such efforts. For example, if there are 600 GOP'ers and 400 Democrats in a state with ten districts, you could put the 600 GOP'ers in six districts and the 400 Democrats in four districts: six seats for the GOP and four for the Democrats. This would create ten utterly "safe seats" which lack political diversity and allow each party to field less impressive candidates.  

You could also put 60 GOP'ers and 40 Democrats in each district, creating ten GOP seats that would be relatively safe, but far more politically diverse and potentially competitive. As members of a political party draw district lines, they have to wrestle with the tradeoff between more seats on average with greater political risk and fewer seats that are safer. 

Political partisans often (naively) imagine that their party leaders are far more virtuous than those in the other major political party. But it should be little or no surprise to learn that gerrymandering is both bipartisan and not all that pervasive at the federal level. With the institutional structures in play, we might expect more trouble when lines are drawn by partisan legislatures, but this activity is still regulated by the courts. And we wouldn't expect many politicians to passionately aim for another seat or two, while looking nakedly partisan and increasing the likelihood of defeat in more competitive seats. (Politicians and bureaucrats usually look to reduce risk, not increase it!)  

Still, gerrymandering does exist. One way to perceive it is to look at the political map. When districts look highly irregular geographically, it at least gives the impression that gerrymandering was the strategic product of "intelligent design". For two terrific examples, check out the 13th and 17th districts in Illinois. 

What do the numbers say and how should we measure it? Assessing representation by party is easy: That’s simply the number of seats held by each party. But what about vote percentages? The most obvious candidate would be the overall vote percentage in each state's House races. But this can be distorted by single-candidate races, where one major political party receives 100%; the other party receives 0%; and fewer voters engage that “race”. (For better/worse, I calculated average vote percentages across all districts in a state.) Given this concern, another reasonable proxy could be the percentage received by the presidential candidate in that year. (The two statistics turn out to be highly correlated, but I'll use both below.)  

Looking at the national numbers, the overall vote percentage (49.8% GOP vs. 47.2% Dem in 2024) implies a slight partisan gerrymandering advantage to the Dems, given that the GOPs only has a slight seat advantage in Congress (220-215). And in October 2025, National Review reported that the GOP controlled state government in 23 states, with 59.3% of the House vote and 75% of the seats. But in the 17 states controlled by Democrats, their House candidates got 56.7% of the vote and 77.7% of the seats.   

Breaking down the analysis to look at each state, I’ve provided all of the data below. But I only see a handful of cases where the numbers reflect the potential for gerrymandering. Some observations of note:  

-There are six single-district states where shenanigans are impossible.  

-Of the nine states with two or three districts, three raise a red flag (all of which favor Democrats): Maine with a 7-12 percentage point Democrat voter advantage and both seats (despite an "independent process"); New Hampshire with a 3-6% Democrat advantage and both seats; and New Mexico with a 6-10% Democrat advantage and all three seats.  

-Of larger states: Wisconsin advantages the GOP (only a 1-3% voter advantage, but 6-2 on seats) and Illinois strongly advantages the Democrats (8-11% advantage, but a whopping 14-3 on seats). Despite "independent" processes, Colorado advantages the GOP (11-15% Democrat advantage, but 4-4 on seats) and New Jersey benefits the Democrats (merely a 6-9% advantage, but 9-3 on seats).  

-In the Deep South, "positive" race-based gerrymandering may help with African-American representation, but hurt Democrats overall. (SCOTUS will soon wrestle with the constitutionality of this in Louisiana v. Callais.) Arkansas has an independent process and a 30-36% GOP advantage, so its four GOP seats are no surprise. In the four more rural states (LA, MS, AL, and SC), the GOP's 24-35% advantage translates into a reasonable 18-6 seat advantage. But in the two more cosmopolitan states (GA and NC), the GOP's 3-8% advantage translates into an impressive 19-9 seat advantage.  

Gerrymandering is probably a secondary concern, but certainly a shiny object for the media and political partisans. Hopefully, politicians and their partisan enablers will devote more energy to bigger concerns: finding good candidates and courageously leading through challenging problems and difficult policy choices.  

	GOPPrezAdv	GOPCongAdv	Seats	GOP	Dem
WY	46	48	1	1	0
SD	29	44	1	1	0
VT	-32	-32	1	0	1
ND	36	40	1	1	0
DE	-14	-16	1	0	1
AK	14	2	1	1	0
WV	42	42	2	2	0
HA	-24	-42	2	0	2
ID	37	38	2	2	0
RI	-14	-24	2	0	2
MT	20	20	2	2	0
ME	-7	-12	2	0	2
NH	-3	-6	2	0	2
NE	20	34	3	3	0
NM	-6	-10	3	0	3
MS	23	40	4	3	1
AR	30	36	4	4	0
UT	21	31	4	4	0
KS	16	18	4	3	1
IA	13	14	4	4	0
NV	4	0	4	1	3
OK	34	47	5	5	0
CT	-14	-19	5	0	5
KY	30	50	6	5	1
LA	22	30	6	4	2
OR	-14	-12	6	1	5
AL	31	56	7	5	2
SC	18	13	7	6	1
MD	-29	-34	8	1	7
MO	18	19	8	6	2
CO	-11	-15	8	4	4
WI	1	3	8	6	2
MN	-4	-2	8	4	4
MA	-25	-84	9	0	9
TN	30	28	9	8	1
IN	19	19	9	7	2
AZ	5	1	9	6	3
WA	-18	-26	10	2	8
VA	-6	-5	11	5	6
NJ	-6	-9	12	3	9
MI	2	-1	13	7	6
NC	3	11	14	10	4
GA	2	4	14	9	5
OH	11	11	15	10	5
IL	-11	-8	17	3	14
PA	1	0	17	10	7
NY	-13	-20	26	7	19
FL	13	10	28	20	8
TX	14	15	38	25	13
CA	-20	-22	52	9	43