Gerrymandering 101

How to rig an election (legally)

Every two years in the United States, we elect new representatives to represent our Districts in Congress. Each State is given a certain number of Districts based on their population, and their legislatures then decide on how these Districts are divided. Basically, the legislatures draw up a map of Congressional Districts for their respective State (or at least, they decide on how that gets done).

Drawing these District maps is the key to rigging an election legally. Since legislatures draw these maps, the first step to rigging an election legally is to take control of the state legislature. But assuming now that your party has control of a state legislature, how do you draw a map to rig the Congressional Elections?

Manipulating maps to benefit your party is called gerrymandering. Before we get on with the details, let us set some conventions. We will use hypotheticals that mimic the real political landscape. In the scenarios we will discuss, there will be two predominant political parties: the Red party and the Blue party. We will be the mapmakers from the Red party, and we will try to benefit our party. Finally, we must seek to fulfill the two rules set out in the Constitution: Districts must be contiguous (1), and each must have around the same population (2).

There are two primary techniques for gerrymandering: cracking and packing. Cracking can be used when there is an area, with a large population, that leans heavily towards one party. The idea is that we should draw District lines so that this area is split into different Districts. In other words, we crack an area’s political influence by spreading their votes. Consider this hypothetical State that must be divided into three Districts each with 15 dots:

Figure 1. Each dot represents a population of approximately 50,000 people. The dots are colored based on which party these 50,000 people will vote for. This State has 30 Red dots and 15 Blue dots for a total of 45 dots. This State has three Districts, and so, each District should contain 15 dots.

We see 15 Blue dots densely clustered around one area; perhaps this area is an urban center which typically have politically likeminded individuals. The 30 Red dots, representing voters of our party, are more spread out; perhaps Red voters tend to live in less dense, more rural areas.

With 30 Red dots and 15 Blue dots split across three Districts, one might expect two Red Districts and one Blue District. But we can crack the Blue area so that we can get all Districts to be majority Red:

Figure 2. This map divides the State into three Districts each with 10 Red dots and 5 Blue dots. And so, come Election time, all three Districts will elect a Red representative.

The dense Blue area in the north of our State has enough voters to completely determine the party that wins one District. If the Blue area were split into two Districts, then it may have large influence in perhaps both Districts. Cracking the Blue area into three Districts spreads out this influence too thinly to win even one election.

The other gerrymandering technique is packing. We can use packing when there are different areas that lean heavily towards one party. Instead of having the two areas influence two different District elections, we can draw a District that puts them together. In other words, we pack a District full of the same type of voter to contain their influence in only one District. Consider this slightly different hypothetical State that again must be divided into three Districts:

Figure 3. Each dot represents the same thing as in the previous hypothetical State. However, in this new State, there are 25 Blue dots and 20 Red dots with the same total of 45 dots. As before, this State has three Districts, and so, each District should contain 15 dots.

Again, we see that Blue voters seem to cluster around more densely populated areas. But this time, there are two major clusters: one near the center of the State slightly northeast and another in the southeast corner. We also see a few other smaller areas with Blue clusters, and as before, Red voters tend to live in sparser areas.

With more Blue dots than Red dots, one might expect that the Blue party will win more Districts than Red. But we can pack most of the Blue dots into one District so that we can get the other two districts to be majority Red:

Figure 4. The packed District colored orange has 15 Blue dots. The other two Districts each have 10 Red dots and 5 Blue dots. And so, this map will produce two Red representatives and one Blue representative.

The two biggest Blue areas have nine dots and six dots respectively. Since each District must contain 15 total dots, if these Blue areas were in a District, then they will be very influential on how elections in their District will turn out. In other words, there needs to be a lot of Red voters in the same District to counteract the Blue voters. Thus, by packing the two Blue areas into one District, we ensure that their votes are not counteracting any Red votes. This then leads to more Red representatives than Blue ones despite having more Blue voters in the state overall.

Typically, we would utilize both techniques in conjuction to effectively gerrymander. A good strategy is to first pack as many Blue voters as you can in as few Districts as possible. Then, crack the remaining areas where Blue voters tend to be more densely populated. In other words: “pack, then crack.” Let's look at our final hypothetical State, this time, with more voters and a total of five Districts:

Figure 5. As before, each dot represents around 50,000 people and is colored based on how they will vote. This State has 50 Blue dots and 25 Red dots, for a total of 75 dots. Since the State has five Districts, each District will have 15 dots each.

We see four major Blue areas that we must pack and crack. The first thing that we might notice is that the Blue area in the center of State is quite populous. In fact, the Blue voters of that area cannot all be fit into one District. Thus, we will save that Blue area for cracking.

In the meantime, we can try to pack the other Blue areas. The second largest Blue area is in the southwest of the State with 15 Blue dots which we can pack into one District. We then try to pack the Blue areas in along the eastern border together. But, that only makes 13 Blue dots, so we will also pack in some of the Blue dots in the center of the State.

Figure 6. The District colored orange and the District colored yellow both will produce Blue representatives as they are unanimously composed of Blue dots.

Now that we have successfully packed 30 Blue dots into two Districts, Red voters are now a majority for the the rest of the three Districts. There are 25 Red dots left, and only 20 Blue dots. We can now crack that Blue area.

Figure 7. This fully Districted map consists of two packed Districts colored yellow and orange. These Districts produce the sole two Blue representatitves. The purple and green Districts have Red voters outnumber the Blue voters 8 dots to 7, producing a Red representative in both of these Districts. The last District, colored pink, have 9 Red dots and 6 Blue dots thus producing a third Red representative.

Cracking is effective when there are voting populations concentrated in one area. The Blue area with a large population in the center of the State will be influential in any one District. But, by splitting its voting influence over three Districts, we ensure that that Blue area cannot determine an election in any District.

The other condition that allows for effective cracking is that our party's voters outnumber the voters of the opposition. Again, the idea of cracking is to ensure that the voters of the opposition do not get a District in which they have the majority influence. By initially packing the most of Blue voters in two Districts, we are able to achieve this second condition for cracking for the last three Districts.

With these gerrymandering techniques, we are able to secure our party's success in future elections. Hence, we flip the narrative of voters choosing which people are put into power. Now, the people in power choose which voters can decide elections.