This is the fifth part of our blog post series, Data Literacy for U.S. Voters.

• In the first part, we touched on the timing of U.S. elections, from the White House all the way down to your local school board.
• In the second part, we tackled the rules for determining winners, featuring the tricky Electoral College.
• In the third part, we sought to understand election polls of various types.
• In the fourth part, Jon Schwabish, author of Better Data Visualizations, showed how the marimekko chart can offer a new perspective on election results

In this fifth and final installment, we’ll learn about a critical outworking of the rules of the U.S. Electoral College System: the swing state.

What is a Swing State?

A swing state, also called a battleground state or purple state, is a U.S. state where no single candidate or party has overwhelming support in securing that state’s Electoral College votes during presidential elections. These states can reasonably “swing” between voting Republican or Democratic in different elections, often decided by narrow margins.

Key characteristics of swing states include:

1. Close election margins (typically less than 3%)
2. A relatively even mix of Democratic and Republican voters
3. Often receive significant campaign attention and resources

If we look at the results of the 2020 U.S. presidential election between Joe Biden (D) and Donald Trump (R), we see that some of the states like California and New York voted heavily in favor of Biden (dark blue circles) and other states like West Virginia and Wyoming voted heavily in favor of Trump (dark red circles):

Notice that seven states are gray colored – neither dark blue nor dark red. In these seven states, the margin of victory was less than 3% of the popular vote, meaning that the winning candidate received less than 3 percentage points more votes that the second place candidate. These seven states were:

• Pennsylvania (20 electoral college votes): Biden +1.15%
• Michigan (16 electoral college votes): Biden +2.77%
• Georgia (16 electoral college votes): Biden +0.22%
• North Carolina (15 electoral college votes): Trump +1.34%
• Arizona (11 electoral college votes): Biden +0.29%
• Wisconsin (10 electoral college votes): Biden +0.63%
• Nevada (6 electoral college votes): Biden +2.39

We can show these seven states on the “tile map” using purple circles, a color often used to designate a swing state due to the fact that it is a blend of the colors blue and red:

If we were to show all 50 states (plus Washington, D.C.) on a scatterplot, with the popular vote encoded horizontally on the x-axis and the number of electoral college votes encoded vertically on the y-axis, we can see these seven states huddled around the 0% reference line that represents the theoretically point at which both candidates receive an equal share of the votes:

If we focus in on just these seven swing states, and look at how they voted in 2020, we can see that Biden won 6 of the swing states, and Trump won 1 of them (North Carolina).

The following dumbbell chart shows the difference in popular vote for each of these swing states. The color of the line connecting the two circles indicates the winning candidate – blue for Biden (D) and red for Trump (R):

What about 2024 swing states?

It should come as no surprise that the swing states of 2020 are also shaping up to be the swing states of 2024. This has not always been the case, of course, and swing states can and do change over the course of time. For example, the state of Virginia was reliably Republican from 1968 through 2004, became a swing state in 2008 and 2012, and has now shifted Democratic in more recent elections.

Nevertheless, an examination of the November 1–2, 2024 poll by Atlas reveals that the 2020 swing states virtually all show polling within the margin of error:

Resources

Here are a handful of helpful online resources related to election data and the electoral college system:

1. AtlasIntel: Public Polls for Swing States – https://www.atlasintel.org/poll/usa-swing-states-2024-11-02
2. FiveThirtyEight: All posts tagged “Swing States” – https://fivethirtyeight.com/tag/swing-states/
3. New York Times: “Tracking the Swing States for Harris and Trump” – https://www.nytimes.com/interactive/2024/us/elections/presidential-election-swing-states.html
4. USAFacts: “What are the current swing states, and how have they changed over time?” – https://usafacts.org/articles/what-are-the-current-swing-states-and-how-have-they-changed-over-time/

These resources provide in-depth information about swing states, also called battleground states.

Common Misconceptions

Here are a few common misconceptions about swing states in U.S. presidential elections:

1. “Swing states are always the same states”: States can shift in and out of swing state status over time. For example, Virginia was once a key swing state but has become reliably Democratic, while Georgia has recently emerged as a new battleground state.
2. “A swing state means the state’s voters frequently switch parties”: Actually, many swing states maintain relatively stable voter bases. The “swing” often comes from close margins between consistent party voters, plus a small but crucial group of persuadable voters or varying turnout patterns.
3. “Swing states are always politically moderate”: This isn’t necessarily true. Swing states can have highly polarized populations that happen to be fairly evenly divided, rather than a large moderate middle.
4. “A competitive race in one type of election means the state is a swing state”: A state might be competitive in Senate or gubernatorial races but not presidential elections, or vice versa. For instance, Massachusetts regularly elects Republican governors but is solidly Democratic in presidential elections.
5. “Swing states always have close results in every election”: Even reliable swing states can occasionally have lopsided results in particular elections due to unique circumstances, candidates, or national trends. One non-competitive election doesn’t necessarily mean a state has lost its swing state status.
6. “Large states with lots of electoral votes are more likely to be swing states”: Population size doesn’t determine swing state status. Some large states like California and Texas are reliably partisan, while smaller states like Nevada and New Hampshire are often competitive.

Critical Thinking Points

As you analyze the role of swing states in American democracy, consider these thought-provoking questions:

• How does the existence of swing states affect political polarization? Consider whether the focus on a few competitive states encourages or discourages extreme political positions, and whether this benefits or harms national political discourse.
• What impact do swing states have on policy priorities? Think about how candidates might shape their platforms to appeal to specific swing state interests, such as corn ethanol in Iowa or auto manufacturing in Michigan, potentially at the expense of national priorities.
• How do demographic changes affect which states become or cease to be swing states? Consider examples like Virginia’s shift due to suburban growth, or Arizona’s changing electoral landscape, and what this suggests about future swing state patterns.
• In what ways might swing state status affect voter engagement across the country? Think about whether reliable “red” or “blue” state voters feel less motivated to participate in presidential elections, while swing state voters might feel heightened pressure and responsibility.