How Gerrymandering Works

Photo Credit: Tom Adamson via Compfight cc

Writing for Bloomberg, Chris Christoff and Greg Giroux explore the math behind gerrymandering in Michigan with some fascinating examples and graphics. The 14th congressional district, for example, looks pretty weird from high up:

Michigan’s 14th congressional district looks like a jagged letter ’S’ lying on its side.

From Detroit, one of the nation’s most Democratic cities, it meanders to the west, north and east, scooping up the black-majority cities of Southfield and Pontiac while bending sharply to avoid Bloomfield Hills, the affluent suburb where 2012 Republican presidential nominee Mitt Romney was raised.

(HT: The Big Picture)


Funny thing is, gerrymandering is ugly but doesn't actually help Republicans that much:

Turns out it's much more due to incumbency and the huge concentrations of Democratic voters in cities, thus leading to more "wasted" Democratic votes under the first-past-the-post system we use. For example, an urban Democratic Congressman might win his district 250K-30K (+220K), while a rural Republican might win 300K-180K (+120K).

One could try to un-gerrymander to create more competitive districts, but these would have the effect of reducing the number of minority districts and would probably be struck down under the Voting Rights Act.

Seminymous Coward

That article is a fine exploration of gerrymandering as applied to Michigan and a couple other states recently. It definitely highlights some population dynamics that make drawing good districts particularly tough. For a generic explanation of how gerrymandering works and how it can be combated, though, I think is superior; its use of generic animal-themed parties is probably better for getting the information across without running afoul of any viewer bias.


I like CGPGrey's video explanation of it. (I like all his gov't videos!)

Caleb B

With as bad a shape as Detroit is in, maybe they could use a Republican running things for a while. Just saying.

Greg Marshall

Sometimes trying to un-jerrymander (new word!) leads to even worse problems. Back in the eighties the school district where I lived was very lopsided. Because of population distribution, my highschool had all but one doctor in town and most of the upper-class in its area. The other high can guess. After 2001, they built a third high school and in the spirit of PC-ness (another new word!) They moved school lines around until every school had the same breakdown of rich/poor, black/white, smoking/non-smoking, idiots/ name it. The school lines twisted and turned around each other so kids on one side of a street went 9 miles to school and on the other 2 blocks...all in the name of fairness.

The problem with jerrymandering for political or any other gain, is there is no fair way to do it. There's always a loser. Undoing what's been done just creates new losers.

What's the answer? How do you fairly make up districts? I'm not quite sure...


Matt R.

A couple of automated methods exist. They can be modified to work with the Voting Rights Act. Have people decide on reasonable (I know hard to define) conditions for a redistricting and let the computer spit out several.


The problem lies in deciding what criteria you use to determine the districts. Political party registration? So is it fair to a) load districts with high majorities of one party or another; or b) create districts with the same number of voters from each party? Same goes for economic status, or race: is it fair to create districts with high majorities of one group, or try to ensure that groups are represented in proportion to their population? In each case, justify your answer :-)

Personally, I'd prefer a land area based districting scheme, where every X square miles gets a representative, regardless of how many people live in that area.

Eric M. Jones

Let's face it: Gerrymandering is simply crooked politics, whoever does it.

I vote we define a state as having a number of unspecified congressional districts. No district borders.


So after the entire jeremiad about those wicked republicans and their wicked wickedness, we fined this gem buried in paragraph 35:

" Also, requirements under the federal Voting Rights Act to maintain two Detroit-centered districts in which minorities are a majority of voters influenced the process."

So Dems have a built-in Gerrymander by federal law that has lasted decades, and Republicans pull a state-level one, and woes is all of us! As Democrats were fond of saying last fall, elections have consequences. Nowhere in the article, except in a quote by a republican lawmaker, is it suggested that Dems are not pissed that gerrymandering happened, but pissed they weren't in charge of it. Maybe next time, Dems take stock at the election prior to redistricting and decide that isn't the time to push for their wishlist, lest they piss off the populace and lose a landslide just before the important part.


Joe J

Worse, this is the first time in 40 yrs that the R had control during gerrymandering time. Haven't seen anyone claim the districts are more disjoined now than they used to be.
I kind of remember a iscussion from 20 yrs ago about someone trying to pass a law that a voting disrtict actually had to be continuous. Not sure what the resolution of that was, probably failed.