Chapter 25 — Exercises

These exercises are designed to be completed individually or in small groups. They are meant to take you out of the textbook and into actual data, actual maps, and actual conversations. Your instructor may grade some, assign others as discussion preparation, or use them as the spine of class meetings. None of them should be confused with private political opinion-formation. They are analytical exercises, and the standard for "doing them well" is rigor and source-citation, not whether your conclusions match anyone else's.

Exercise 1 — Pull DW-NOMINATE data on a member of Congress

Visit Voteview.com (the public archive of DW-NOMINATE scores). Choose any current member of the U.S. House or Senate — your own representative, or someone you find interesting. Record their first-dimension NOMINATE score. Record the score of the median member of their party in the chamber for the current Congress. Record the score of the median member of the opposing party for the current Congress. Compute the gap between the two party medians.

Now look at the same member's score from earlier Congresses (if they have served before), and at the party medians from earlier Congresses. Construct a small table showing the trajectory.

In two paragraphs (around 400 words total), describe what the data shows about your member's polarization relative to their party median, and about the broader trajectory of inter-party distance over the time period you examined.

What this teaches: That polarization is not a vague impression — it is a measurable property that you can pull from public data in roughly fifteen minutes.

Visit the ANES (American National Election Studies) website at electionstudies.org. Locate the feeling-thermometer time series for the major parties. (Look for "Time Series Studies" or "Cumulative Data File.")

Construct a chart (by hand on paper, in a spreadsheet, or in any tool you prefer) showing three lines from 1980 to the most recent data: average warmth toward own party, average warmth toward opposing party, and the cross-party gap. Annotate the chart with major political events you think might explain inflection points (the rise of Gingrich in 1994, the Obama election in 2008, the Trump election in 2016, January 6, 2021, the 2024 election).

In two paragraphs, describe what the chart shows. Pay particular attention to whether the changes are mostly driven by declining warmth toward the other party or by rising warmth toward one's own party.

What this teaches: That affective polarization, as measured, is overwhelmingly a story about negative feelings toward the opposing party rather than positive feelings toward one's own.

Exercise 3 — Identify your district's PVI

The Cook Partisan Voting Index (PVI) is a measure of how much more Republican or Democratic a congressional district is than the country as a whole, based on the previous two presidential elections. Find your own congressional district's current PVI (Cook Political Report publishes the data; ballotpedia.org also lists it; Wikipedia maintains the table).

Record: - Your district number and the name of your current representative. - The current PVI (e.g., R+8, D+3, EVEN). - The 2024 House election margin in your district. - Whether your representative faced a primary challenge in their last cycle, and if so, was the challenger to their left or to their right.

In one paragraph, describe what these numbers tell you about how competitive your district is in the general election versus how competitive it is in the primary, and about which electorate is most likely the decisive one for your representative's behavior.

What this teaches: That polarization is not just a national phenomenon; it has a structure that you can locate yourself in by looking at four publicly available numbers about your district.

Exercise 4 — Steel-man symmetric polarization

In two paragraphs (around 400-500 words total), make the strongest possible case for the claim that both major parties have polarized substantially over the past forty years and that focusing on one side's movement misrepresents the phenomenon. Draw on real examples: positions held by mainstream Democrats in 1990 versus 2024 (consider immigration, identity, education, the role of the administrative state); positions held by mainstream Republicans in 1990 versus 2024 (consider trade, foreign policy, election integrity, the role of the administrative state). Be specific. Cite at least three distinct issue areas.

The point of this exercise is not to conclude that the parties have moved equivalent distances. The point is to be able to articulate the strongest version of the symmetric-polarization argument, regardless of which side you instinctively find more sympathetic.

What this teaches: Steel-manning is a discipline. Before you reject a claim, you should be able to make the strongest case for it.

Exercise 5 — Steel-man asymmetric polarization

In two paragraphs, make the strongest possible case for the Mann/Ornstein/McCarty claim that congressional Republicans have moved further from the center than congressional Democrats have over the past forty years. Draw on the DW-NOMINATE data (see Exercise 1), specific examples of legislative behavior (the willingness to shut down government over policy demands, votes on debt-ceiling increases, willingness to use procedural mechanisms in novel ways), and changes in party leadership behavior (Speaker selection, intra-caucus discipline).

Then, in a third paragraph, articulate what you see as the strongest objections to this claim. Engage with the strongest objection seriously, not the easiest-to-rebut version.

What this teaches: Even the most empirically supported claim has serious objections worth engaging.

Exercise 6 — The Big Sort in your county

Find your home county on a 2024 presidential-election results map. (Politico, the New York Times, and 270toWin all publish county-level results.) Record: the margin between the two major-party candidates in your county in 2024, the margin in 2008 (Obama-McCain), and the margin in 1992 (Clinton-Bush-Perot, two-party share).

If your county has shifted by more than 10 points in either direction over this 32-year span, describe what you know about the demographic, economic, and cultural changes in your county that might explain the shift. If your county has stayed roughly the same, describe what you know about the local conditions that have produced consistency. If you do not know enough about your county to write this paragraph, find out — local newspaper archives, county-level Census data, and local-history sources are accessible.

What this teaches: The "big sort" is not just a national pattern. It happens in specific places for specific reasons. Your county is one of those places.

Exercise 7 — Democracy Audit: polarization indicators in your community

The progressive Democracy Audit project asks you to examine your own political environment. For polarization specifically, document the following in your community:

  1. Does your local newspaper still exist? If so, how often does it publish? Does it have a local political reporter? Does it report on local government meetings? Does it make endorsements?
  2. How many of the candidates running for local office (school board, city council, mayor, state legislature) in the last election cycle ran with party labels? How many ran as nonpartisan? How many faced a primary challenge?
  3. Are there active local civic organizations that bring together people across partisan lines? Examples might include League of Women Voters chapters, local interfaith groups, civic clubs (Rotary, Kiwanis, etc.), community-foundation-sponsored civic dialogues, or local Braver Angels chapters.
  4. Have you, in the past year, had a substantive political conversation with someone you knew to disagree with you? Describe the conversation. What did you learn? What did you not learn?

In one page (~600 words), describe what your findings tell you about how polarization manifests at the community level near you.

What this teaches: Polarization at the national level is downstream of the dissolution or strengthening of cross-cutting community institutions at the local level. You are an actor in those institutions.

Exercise 8 — Compare U.S. polarization to one other democracy

Choose one other democracy from the following list: United Kingdom, Canada, France, Germany, Israel, Brazil, Sweden, Japan. Find a recent (2020 or later) academic or journalistic source on polarization in that country. (V-Dem Institute reports, Journal of Democracy articles, Foreign Affairs essays, and country-specific political-science articles in The Annals of the American Academy of Political and Social Science are good starting points.)

Compare the polarization pattern in that country to the U.S. pattern as described in this chapter. Address: Are the parties as polarized? Is affective polarization comparable? Are the underlying causes (geographic sorting, media, primary system, etc.) similar or different? Has polarization in that country been rising, falling, or stable over the past decade?

In two paragraphs, describe what the comparison teaches you about the U.S. case. Is the U.S. unique, or is it part of a broader pattern? What features of the U.S. system look distinctive in comparative perspective?

What this teaches: Comparative perspective is the antidote to American exceptionalism in either direction. The U.S. is not the only polarized democracy and is not the most polarized democracy. It is one of many.

Optional extension exercise — Conduct a perception-gap survey

If your instructor allows, conduct a small perception-gap survey among classmates, friends, or family. Ask Republicans (or right-leaning respondents): "What percentage of Democrats do you think believe [specific extreme position]?" Ask Democrats (or left-leaning respondents): "What percentage of Republicans do you think believe [specific extreme position]?" Choose positions for which you can find actual survey data on the median Democrat or Republican.

Compare estimates with reality. How large are the perception gaps you find? How do they compare with the More in Common research described in 25.9.5? Write a short reflection (300 words) on what you learned about your own perceptions and those of people around you.

What this teaches: That you yourself are likely subject to perception-gap effects, and that the act of measuring them can shift them.

Exercise 9 — Trace one piece of legislation through polarized voting

Choose any major piece of federal legislation passed since 2010 — the Affordable Care Act (2010), the Tax Cuts and Jobs Act (2017), the American Rescue Plan (2021), the Inflation Reduction Act (2022), the Infrastructure Investment and Jobs Act (2021), or another of comparable significance. Look up the House and Senate roll-call votes (govtrack.us, Congress.gov, or clerk.house.gov publish them). Record:

  • The total Yea/Nay split.
  • The Yea/Nay split within each party.
  • Whether any members of the majority party voted against, and whether any members of the minority party voted for.
  • Which procedural mechanism the bill used (regular order, reconciliation, conference committee, etc.).

Now compare with a comparable piece of legislation from before 1995 — the 1986 Tax Reform Act, the 1990 Clean Air Act Amendments, or the 1996 welfare reform. Look at the cross-party support for those bills.

In two paragraphs (around 350 words), describe what the comparison shows. How has the structure of major-legislation passage changed? What do these voting patterns suggest about the institutional manifestation of polarization?

What this teaches: That polarization is not just a feeling or a measurement on a scale — it is a property of how Congress actually passes (or fails to pass) major legislation, visible in the roll-call record itself.