第1章
The Politics of Identity: How America's Tribes Tore Us Apart
In 2016, something extraordinary happened that wasn't extraordinary at all. Donald Trump, a candidate who violated every norm of political behavior, secured the presidency despite losing the popular vote by nearly 3 million ballots. The truly remarkable aspect? The voting patterns remained strikingly consistent with previous elections. Republicans still voted Republican (88% compared to 93% in 2012), and groups Trump directly attacked showed minimal shifts in voting behavior. This stability reveals the enormous weight party polarization now exerts on American politics-a force so powerful it normalizes even the most unconventional candidates.
Ezra Klein's "Why We're Polarized" has become required reading in political science departments nationwide and a favorite of thought leaders from Barack Obama to Mark Zuckerberg. The book's genius lies in examining American polarization not through the lens of individual villains but through interlocking systems that shape our political decisions. Klein's analysis has proven prescient, with polarization intensifying since publication, making this exploration of our tribal tendencies more relevant than ever.
第2章
The Birth of Modern Polarization: From Muddled Parties to Ideological Purity
In 1950, the American Political Science Association published what today reads like satire: "Towards a More Responsible Two-Party System." These scholars actually pleaded for more polarization, lamenting that parties contained too much ideological diversity and worked together too easily. They worried voters couldn't make "intelligent choices" between parties that weren't clearly differentiated.
The fundamental issue was that political parties should function as shortcuts for voters. With countless complex policy decisions to make, no citizen can develop sufficient expertise on everything. Parties were meant to be "indispensable instruments of government" providing voters with clear alternatives. But in 1950, the parties weren't honoring voters' intentions. A Minnesota Democrat voting for liberal Hubert Humphrey would also empower conservative Strom Thurmond in the Senate majority.
Fast forward to today, and that problem has been thoroughly solved. Between 1972-1980, the correlation between Democratic House votes and Democratic presidential votes was .54. By 2018, it had reached an astonishing .97-making presidential preference an almost perfect predictor of House votes. The average partisan gap on key issues increased from 15 to 36 percentage points between 1994 and 2017.
This transformation manifests in governance too. Reagan and Bush Sr. raised taxes and supported environmental protections that would be unthinkable in today's GOP. Clinton worked with Republicans on welfare reform and declared "the era of big government is over." Medicare received substantial Republican support in 1965, while Obamacare-despite incorporating Republican ideas-received zero Republican votes.
As parties have diverged, even inattentive voters today understand party differences better than political junkies did in 1980. Increasingly, Americans see the opposing party as "a threat to the nation's well-being." This heightened partisanship isn't irrational-it's a logical response to parties that have become fundamentally different.
第3章
The Racial Realignment: How Civil Rights Transformed American Politics
On August 28, 1957, Strom Thurmond launched the most famous filibuster in American history, speaking for over 24 hours against a civil rights bill. This performance was more spectacle than substance-southern senators had already gutted the bill's most meaningful provisions. Thurmond's solo filibuster didn't endanger the bill but boosted his career as a vocal defender of the South's racial order.
The Democratic Party's control of the South was hegemonic, with Democrats occupying up to 95% of elected offices through voter suppression and violence. African American voter registration plummeted from 85-94% after the Civil War to just 5% by 1944, with some Black Belt counties having no black voters whatsoever. This authoritarian system persisted because it served national Democrats' interests-they needed southern votes for their agenda.
The Civil Rights Act's passage triggered the Dixiecrats' demise, allowing southern conservatives to join Republicans and northern liberals to join Democrats. This ideological sorting created two distinct parties with no overlap-no House Democrats more conservative than any Republicans or vice versa.
The transformation is stark. In 1952, demographic differences between parties were modest, with most groups showing less than 10 percentage point differences in party representation. By 2012, while only 9% of Republicans were nonwhite, 43% of Democrats were. Religious divides are equally dramatic-Republicans' largest religious group is evangelical Protestants, while Democrats' is the religiously unaffiliated.
These demographic shifts reflect deeper value changes. By 2017, 64% of Democrats but only 47% of Republicans believed you don't need God to be moral. The parties are now divided along fundamental identity lines-race, religion, geography-that generate greater intolerance than traditional policy disagreements like taxes or spending.
Our political affiliations increasingly reflect fundamental psychological differences. Research shows Democrats and Republicans are distinguished by basic psychological dispositions related to openness to experience-with liberals generally more comfortable with uncertainty and change, while conservatives prefer order and tradition. For politically engaged citizens, politics becomes less about "what will this policy do for me?" and more about "what does support for this policy say about me?"-transforming politics from transactional problem-solving into psychological self-expression.
第4章
The Tribal Mind: How Group Identity Hijacks Our Thinking
Henri Tajfel's groundbreaking 1970 experiments revealed how easily humans sort themselves into "us" versus "them" categories and discriminate against outsiders-even without rational reason. As a Polish Jew who survived WWII by hiding his identity only to return and find most of his family murdered, Tajfel developed a profound understanding of group identity's power.
His famous experiments demonstrated that even arbitrary, meaningless group assignments (based on dot estimation or art preferences) immediately triggered in-group favoritism. Disturbingly, participants often preferred giving their group less money in absolute terms if it meant maintaining a larger advantage over the other group-"gratuitous discrimination" with no material benefit.
Sports fandom perfectly illustrates our deep psychological need to sort "us" from "them" and witness our group triumph over outsiders. Despite having no material stake in the outcomes, millions attach their happiness to games they don't play and victories they don't personally benefit from. This tribal attachment is so powerful it can lead to violence-with dozens of North American sports riots resulting in thousands of arrests and multiple deaths.
Research shows partisans behave more like sports fans than thoughtful citizens. A study by Miller and Conover found that while policy positions play some role in political behavior, partisan identity and negative feelings toward opponents drive political engagement far more powerfully. Pew research confirms this: Republicans with "very unfavorable" views of Democrats were 12 points more likely to vote regularly than those with merely "mostly unfavorable" views, while deeper affection for their own party increased voting by only 6 points.
Barack Obama's transformative 2004 Democratic Convention speech claimed "there's not a liberal America and a conservative America" but "the United States of America." Despite being the most thoughtful politician with historical perspective, Obama himself became the most polarizing president in polling history before Trump. His presidency revealed the paradox that our nonpolitical identities don't overcome our political divisions-instead, our political identities increasingly polarize our other identities.
We each carry multiple identities-racial, religious, geographical, cultural, professional-that can be activated in different contexts. As Lilliana Mason explains in "Uncivil Agreement," American partisanship has become a "mega-identity" where a single vote indicates not just political preference but religion, race, ethnicity, neighborhood, and even consumer habits. The 2004 Club for Growth ad attacking Howard Dean as a "tax-hiking, government-expanding, latte-drinking, sushi-eating, Volvo-driving" liberal perfectly captured this weaponization of nonpolitical markers.
第5章
The Motivated Mind: Why Smart People Believe Dumb Things
The individual mandate's political journey reveals how tribal thinking overrides policy consistency. It first appeared in a 1989 Heritage Foundation brief as a market-oriented alternative to Democratic healthcare proposals. Conservative economist Milton Friedman later supported "a requirement that every U.S. family unit have a major medical insurance policy." The mandate made its legislative debut in 1993 in the Republican alternative to Clinton's healthcare bill, sponsored by John Chafee and co-sponsored by 18 Republicans including Bob Dole.
Yet when Democrats adopted this conservative idea, Republicans suddenly viewed it as unconstitutional tyranny. When fourteen state attorneys general challenged the Affordable Care Act's individual mandate in 2010, legal experts dismissed their arguments as nearly frivolous. Sanford Levinson called it "close to frivolous," while Orin Kerr put the chances of courts invalidating it at "less than one percent." Yet Republican-appointed judges repeatedly ruled against the mandate while Democratic appointees upheld it.
This pattern isn't unique to healthcare. In 2013, Yale Law professor Dan Kahan tested why good data fails to resolve political debates. He gave 1,000 Americans a math skills assessment followed by two versions of a brainteaser: one about skin cream effectiveness and another using the same numbers but framed around gun control. With the skin cream problem, math skills predicted success regardless of politics. But with the gun control version, ideology drove answers-liberals excelled when the data showed gun control worked, conservatives when it showed the opposite. Remarkably, stronger math skills actually widened this partisan gap by 45 percentage points.
Kahan found similar results with climate change: among skeptics, scientific literacy increased skepticism rather than reducing it. This explains why climate denialism often comes packaged in scientific-looking charts and citations. The pattern extends to expert credibility-people rate researchers as "experts" primarily when they agree with their conclusions.
Kahan argues this "identity-protective cognition" is rational: "The cost to her of making a mistake on the science is zero," but "the cost of being out of synch with her peers potentially catastrophic." For someone like Sean Hannity, accepting climate change would destroy relationships, viewers, and possibly his career. As David Brooks experienced when breaking with conservatives over Trump, "my weekends were just howling silences."
第6章
Demographic Threat: How America's Changing Face Drives Political Fear
In 2008, Barack Obama symbolized change as hopeful, while in 2016, Donald Trump wielded it as a threat, promising to "make America great again." This contrast reflects America's defining demographic transformation: the country is rapidly becoming more diverse. By 2013, most American infants were nonwhite, and by 2045, America will become majority-minority. While Black, Hispanic, Asian, and mixed-race populations grow, the non-Hispanic white population uniquely is projected to shrink from 199 million in 2020 to 179 million in 2060.
Psychologists Maureen Craig and Jennifer Richeson discovered that merely exposing white Americans to information about becoming a demographic minority significantly shifted their political views rightward. In one study, white political independents who read that California had become majority-minority were 13 points more likely to favor the Republican Party than those who hadn't received this information. A follow-up study showed that whites who read about the projected 2042 minority-majority transition shifted toward conservative positions not just on race-related issues but across the political spectrum.
Despite hopes that Obama's 2008 election signaled a post-racial America, UC Irvine political scientist Michael Tesler shows that his presidency actually further racialized American politics. Attitudes on race began shaping attitudes on virtually all political questions-the black-white divide on Obamacare was 20 points larger than for Clinton's health proposal. By 2012, Obama won just 39 percent of the white vote-less than Dukakis had in 1988.
Trump didn't crash into American politics like a comet-he was a savvy marketer who read the changing political landscape. Conservative politics was already becoming more racialized in response to Obama, with figures like Rush Limbaugh claiming whites were becoming "the new oppressed minority." Bill O'Reilly declared after Obama's 2012 victory that "the white establishment is now the minority." A 2016 poll found 57 percent of whites agreed that discrimination against whites was as big a problem as discrimination against minorities.
The debate over Trump's rise often pits economic anxiety against racial resentment, but evidence suggests racial resentment actually activated economic anxiety, not vice versa. Before Obama's presidency, racial attitudes didn't affect whites' economic perceptions, but by 2012, racial resentment strongly predicted economic pessimism. After Trump's election, the most racially resentful became the most economically optimistic, despite minimal economic changes.
第7章
The Media Machine: How Information Systems Amplify Our Divisions
Drawing on fifteen years as a political journalist across multiple platforms, Klein has learned that almost no one follows politics out of obligation-they do so as a hobby, like following a sport or band. Political media must compete with everything else for audience attention, from sitcom reruns to video games to sleep itself.
This war for attention is unprecedented. In 1995, political news consumers had limited options-hometown papers, radio stations, nightly newscasts, and perhaps CNN. By the mid-2000s, they could access virtually any newspaper worldwide, countless blogs, multiple cable news networks, and vast historical archives through Google.
Yet despite this information abundance, Americans weren't becoming more politically knowledgeable or engaged. Princeton political scientist Markus Prior resolved this paradox: the digital revolution offered not just more information but more choice of information. The explosion in political media was matched by explosions in media covering everything else-from cooking to celebrities to cat pictures.
In today's choice-driven media landscape, political journalism serves those already interested in politics while trying to create more such people. This differs fundamentally from when political news was part of a monopolistic bundle-when citizens had only one local newspaper or three broadcast networks, the business model aimed to appeal to the widest possible audience.
Media often functions as "a conspiracy to surface the loudest voices"-not through actual conspiracy but through market demands, similar to how food industries pack products with salt, fat and sugar. Cable news runs on ratings, with shows evaluated by quarter-hour metrics. As Chris Hayes of MSNBC admits, "We're wedding DJs. And the wedding DJ's job is to get you on the floor."
When confronted with opposing political views, we don't moderate our positions-we often become more extreme. A groundbreaking study paid over 1,200 Twitter users to follow bots retweeting content from the other side of the political aisle. The result? Republicans became substantially more conservative, while Democrats showed slight increases in liberal attitudes. This contradicts the popular "echo chamber" theory that suggests exposure to counterevidence would reduce polarization.
The fundamental dilemma of journalism is that we don't merely reflect reality-we shape it. By deciding what's "newsworthy," media outlets become powerful political actors rather than neutral observers. Trump weaponizes this dynamic by deliberately lobbing grenades into our deepest social divides. His outrageous statements-from calling Mexicans rapists to proposing Muslim bans-dominate media oxygen precisely when his campaign needs it most.
第8章
The Broken System: How Our Democracy Amplifies Division
Before joining George W. Bush's campaign team, Matthew Dowd had been a Democratic consultant-a rare persuadable voter himself. Analyzing the 2000 election results, Dowd discovered that true independents-voters genuinely undecided between parties-had plummeted from 22% of the electorate to just 7%. This revelation challenged conventional campaign wisdom that had been allocating 80% of resources to persuasion and only 20% to base motivation.
The decline of persuadable voters might seem advantageous for political parties, but parties themselves are weakening while partisanship strengthens. This paradox explains how Trump could win the Republican nomination despite party elites' horror. Fifty years ago, nominations were controlled by party officials in smoke-filled rooms who served as gatekeepers against demagogues. Today's primary system favors candidates with intense supporter bases rather than broad appeal.
When Joe Wilson shouted "You lie!" during Obama's healthcare speech, the breach of decorum transformed him from backbencher to GOP celebrity overnight. Wilson raised nearly $2 million from conservatives nationwide, while his Democratic opponent raised $1.5 million-both capitalizing on national partisan networks rather than local support. This illustrates how campaign finance has changed politics. Research shows that when parties control fundraising, legislatures are less polarized. When candidates must raise money themselves, they appeal to highly partisan donors through ideology, identity, or transactional promises.
The nationalization of fundraising incentivizes candidates to focus on polarizing issues that energize donors nationwide rather than local concerns. While small donors are polarizing, institutional donors are corrupting-they give as investment rather than identity expression. American politics thus responds to two types: the polarized and the rich.
Trump's hostile takeover of the Republican Party defied conventional wisdom. Despite savaging Republican leaders and policies, Trump secured the nomination and ultimately the presidency-without facing the electoral punishment that doomed previous ideological insurgents like Goldwater in 1964 or McGovern in 1972. The key difference? Intensified polarization. Threat has become as powerful a motivator as love.
The most powerful critique of America's political system came from Spanish political sociologist Juan Linz in 1990. Having lived through governmental failures, Linz identified that presidential systems like America's tend to collapse elsewhere because they create irresolvable conflicts between executive and legislative branches when different parties control each. America survived as the only long-standing presidential democracy because our political parties were historically "diffuse"-ideologically mixed rather than rigidly polarized. But as our parties have sorted ideologically, the system has destabilized.
第9章
The Asymmetric Divide: Why the Parties Aren't the Same
When Thomas Mann and Norm Ornstein moved to Washington in 2005, they had become the quintessential balanced political experts-Mann at the center-left Brookings Institution and Ornstein at the conservative American Enterprise Institute. Their bipartisan credibility made them the media's go-to congressional analysts, embodying the assumption that both parties were ideologically opposed but otherwise equivalent.
But as American politics evolved, Mann and Ornstein grew increasingly uncomfortable with this false equivalence. In their 2012 book "It's Even Worse Than It Looks," they spent their accumulated political capital to deliver an uncomfortable truth: the Republican Party had become "an insurgent outlier"-ideologically extreme, contemptuous of compromise, dismissive of facts and evidence, and hostile to the legitimacy of its opposition. The Democratic Party, while "no paragon of civic virtue," remained more ideologically centered, protective of government's established role, and open to incremental policy changes through negotiation.
The Democratic Party's diversity has become its immunological defense against extreme polarization. Unlike Republicans, who are overwhelmingly dependent on white Christian voters, Democrats must appeal to a coalition of liberal whites, African Americans, Hispanics, Asians, and people of various faiths and worldviews. This diversity forces Democrats to adopt a transactional rather than purely ideological approach.
The Democratic coalition isn't just demographically diverse-it's informationally diverse too. Pew Research found that "consistent liberals" trust a wide variety of media sources spanning from center-right to left, including mainstream outlets like ABC, CBS, CNN, and the New York Times, but also more ideological sources. By contrast, "consistent conservatives" trusted only a handful of deeply ideological sources: Fox News, Breitbart, the Wall Street Journal, the Blaze, the Drudge Report, and talk radio programs like Sean Hannity, Glenn Beck, and Rush Limbaugh.
America's political system privileges sparse rural areas over dense urban ones, creating a structural advantage for Republicans. Democrats consistently win more votes nationally but hold less power. As Jonathan Rodden notes, "In most democracies, the path to victory is simple: win more votes than your competitors. For the Democratic Party in the United States, however, this is often not good enough."
This geographic advantage has prevented Republicans from moderating their message despite losing the popular vote in six of seven recent presidential elections. Instead, the party has learned to win power by winning land rather than hearts and minds, creating a dangerous dynamic where a group accustomed to power feels its control slipping away.
第10章
Finding a Path Forward: Managing Polarization in Ourselves and Our System
Polarization itself isn't inherently problematic-sometimes it's a solution. Modern polarization has roots in the civil rights era, when Democrats embraced racial equality and Republicans provided a home for white backlash. The alternative to polarization is often not consensus but suppression.
However, our current polarization is the logical outcome of complex incentives, technologies, identities, and political institutions. Absent an external unifying force like war, these divisions will likely persist. Rather than trying to reverse polarization, we need to reform our political system to function amid it.
Given the difficulty of bipartisan agreement, we should "bombproof" government operations against political disaster. The debt ceiling is the most obvious target-a bizarre mechanism that could transform routine congressional bickering into global financial crisis. Congress's broken budgetary process also needs reform. Instead of proper budgeting, Congress relies on "continuing resolutions" that prevent long-term fiscal planning.
Exposure to democracy has functioned as an immune system for Democrats, while Republicans have been warped by winning elections without needing majoritarian agendas. Politicians would adopt less polarizing approaches if forced to build broader coalitions. At the presidential level, this means eliminating the Electoral College. For the House, proportional representation with multimember districts and ranked-choice voting would ensure more voters matter. For the Senate, eliminating the filibuster would restore accountability.
Beyond systemic changes, we must recognize how political systems manipulate us by activating our political identities to drive engagement. All politics is influenced by identity because human cognition is shaped by identity. While we can't eliminate identity's influence, we can become mindful of which identities are being activated and intentionally cultivate others.
We give too much attention to national politics, where our individual influence is minimal, while neglecting state and local politics where our voices matter more. Of America's over 500,000 elected officials, only 537 serve at the federal level-yet these are the ones we focus on most intensely.
American politics has no end state or perfect solution-only the best we can do right now. What works in one era fails in the next. Today's successes will inevitably ossify into tomorrow's frustrations. The goal isn't to find a static answer but to progress with minimal violence.
Despite our current challenges, America has been worse at almost every other point in our history. The mid-20th century that many romanticize featured political assassinations, violent suppression of civil rights, urban riots, illegal bombing campaigns, and Watergate. If we can do slightly better tomorrow, we'll be doing much better than we ever have before.
