Supporters of President Donald Trump clash with anti-Trump protesters during a rally against his policies in Santa Monica, California.Mark Ralston / AFP / Getty

Americans’ views on impeachment are neatly split along partisan lines. The latest polling averages, tracked by the website FiveThirtyEight, show that 84 percent of Democrats now support impeachment, close to the highest level since at least August 2018, when the site started collecting polls on the issue. By contrast, only 11 percent of Republicans support impeachment, a number that has stayed fairly consistent over the past year and a half. This gulf in Democrats’ and Republicans’ views is more than just partisanship, however. It’s the latest evidence that political tribalism has taken over nearly every part of American life.

According to a growing body of political-science research, Americans largely no longer feel a shared sense of national identity. Democrats and Republicans see their political opponents as enemies with totally incomprehensible beliefs and lifestyles. On impeachment, members of the two parties see things radically differently, not just because they have dissimilar political opinions, but because they have entirely divergent views on how to approach life. The vicious impeachment fight ahead may further exacerbate polarization in America, leaving Republicans, Democrats, and everyone in between feeling even more suspicious of one another.

When I asked Michele Margolis, a political scientist at the University of Pennsylvania and the author of the 2018 book From Politics to the Pews, how much of an effect impeachment would have on the country’s polarization, she didn’t hesitate: “Huge!” American democracy functions only when each side is able to recognize the other as legitimate and accept the outcome when it loses. Over the past two decades in particular, that mutual respect has been significantly undermined, in part because Americans have so thoroughly sorted themselves into their respective political camps. “We’re now in a world where we really don’t have to talk to people who don’t think and look like us politically,” she said. But “it’s important to interact with people who don’t look like you [and] don’t think like you. That’s how we recognize the other side as people, and tolerate them and their political views.”

America’s great self-sorting is partly responsible for the two divergent narratives that have emerged on impeachment. Democrats can’t believe Republicans are willing to give President Donald Trump a pass for basically anything, including asking a foreign leader to investigate the family of one of his political opponents. Republicans, on the other hand, see the latest phase of the impeachment inquiry as a deceitful, partisan ploy from Democrats desperate to get Trump out of office. These are not just two ways of interpreting the same set of facts, with a gentleman’s agreement to disagree. They’re totally separate understandings of reality, based on the assumption of the other side’s bad faith. “If you truly believe that this is a witch hunt, and the Democrats have nothing on President Trump,” Margolis said, “it’s easier to have anger toward [the other side]. It’s easier to have hostility toward them.”

According to research from two scholars at the University of North Carolina at Chapel Hill, Marc Hetherington and Jonathan Weiler, Americans’ assumptions about their political opponents’ bad faith is rooted in something deeper than partisan affiliation. People on opposite sides of the political spectrum actually have non-overlapping worldviews, which makes it hard for them to see anything legitimate in their political opponents’ views. The archetypes Hetherington and Weiler draw in their 2018 book, Prius or Pickup?, are intuitively recognizable: Americans with a more conservative, or “fixed,” orientation value obedience in their children and strength in their leaders. They often fear the world around them, and prize stability and tradition over experimentation and change. By comparison, Americans with a more liberal, or “fluid,” worldview strive to raise independent, curious children and see empathy and tolerance as the most noble qualities a leader can embody. They believe in questioning authority and abhor performative shows of toughness.

This sharp worldview divide helps explain the current dynamics in Washington around impeachment—why people are so angry, and why each side automatically counts each new revelation as evidence for its case. “When people hate the other side so much, they’ll resist just about anything, any kind of information, that would be beneficial to that other side,” Hetherington told me. Americans’ “partisan bias is so strong that even in the absence of strong counterarguments on behalf of the president, we’re seeing no movement in public opinion about impeachment.”

The depth of America’s polarization is what makes this impeachment inquiry so different from the ones faced by Richard Nixon in the 1970s and Bill Clinton in the 1990s. Especially 45 years ago, partisanship “was not anchored in these fundamental, psychological worldviews,” Weiler told me. The two parties had not yet turned politics into a series of moral litmus tests on abortion, LGBTQ rights, and other highly charged issues. Policy debates were just that: debates, with space for respect and compromise. By the Clinton years, this dynamic had started to shift at the elite level, but members of the two political parties had not yet fully sorted themselves by fundamental differences in worldview, Hetherington said. “It’s the marriage of worldview and partisanship that creates this toxicity to politics,” he told me. “It’s a volatile marriage, to say the least.”

Not everyone in America fits neatly into these camps—fixed versus fluid, conservative versus liberal, Republican versus Democrat. The country is full of people with mixed identities and beliefs who occupy some point in the middle of the political spectrum. But their lives are still influenced by the people who listen to talk radio, read partisan websites, and watch MSNBC or Fox News. Hetherington and Weiler compared people with intensely partisan identities to smokers: Their exhalations shape the environment of the people around them, even those who aren’t smokers themselves.

This effect makes it harder for people in the gray space of politics to weigh evidence for themselves and make up their own mind, a process that is especially important on a high-stakes issue like impeachment. It’s impossible to know what lies on the other side of this inquiry—how Trump will react as new evidence emerges, how a trial in the Senate will play out, how it all will affect the 2020 election. But one outcome seems sure: This bitter fight will make it even harder for Americans to see their political opponents as reasonable humans. Instead, impeachment may end up serving as one more guidepost, pointing Republicans and Democrats to their respective sides.

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