Matt Rourke / AP

The bitter battle that culminated in last night’s House vote to impeach President Donald Trump foreshadows an even more dramatic struggle to come over his reelection. It’s a contest that will likely feature a historic mobilization of each party’s coalition, and will test widening satisfaction about the economy against widespread unease over Trump’s behavior, values, and respect for the rule of law. Indeed, the 2020 result may hinge on whether that tailwind of economic contentment proves more powerful than the headwind of voters’ doubts about Trump’s behavior—or vice versa.

The starkest message to be gleaned from the impeachment struggle may be that red and blue America have almost completely separated into hostile camps. Polls have shown an almost complete partisan split over impeachment, with 90 percent or more of Democrats supporting it and virtually all Republican partisans in opposition. This continues a pattern of unprecedented unity within the parties—and division between them—that has characterized virtually every moment of Trump’s presidency. The gap between presidential approval ratings among Democratic and Republican voters has been widening steadily since the 1970s, but under Trump the trend has peaked. Across a wide array of surveys, Trump routinely receives positive ratings from about 90 percent of Republicans and fewer than 10 percent of Democrats.

Impeachment has vividly captured this polarization. To a much greater degree than Democrats during Bill Clinton’s impeachment, congressional Republicans have locked arms around their president. In the House Intelligence and Judiciary Committees, nearly every Republican defended Trump or tried to discredit the witnesses against him, rather than trying to independently assess the underlying facts of the controversy. Nor have Republicans in either chamber expressed any resistance to Trump’s systematic defiance of Congress’s oversight requests and his incendiary accusations that treasonous Democrats are staging a coup.

House Democrats showed much more commitment to exploring the evidence and grounding their case against Trump in the findings of the House’s investigation. But they, too, supported their party on every key vote, swatting away GOP charges that the process was unfair. An effort by some moderates to explore censure as an alternative to impeachment quickly fizzled. And despite much uncertainty about the intentions of the 31 House Democrats in swing districts that voted for Trump in 2016, all but two of them voted last night to impeach him.

The partisan unanimity on all these questions offers yet more evidence that 2020 could see historic turnout from each party’s core voters. Some experts have predicted that 2020 could produce the highest participation among eligible voters since the 1908 presidential election, before women had the right to vote.

In this “Battle of the Bulge” between two divergent Americas, small differences in both parties’ ability to mobilize supporters may tip the outcome. But in such an evenly matched conflict, small slivers of erosion at the edges of each coalition—or minor shifts in the opinions of any remaining swing voters—could also prove decisive. Recent trends in public opinion offer hints at the competing forces that will weigh on the ambivalent voters who could decide next year’s result.

In several polls, Trump’s approval rating edged up slightly during the impeachment struggle, though it remained at 45 percent or below in almost all surveys. Those numbers may reflect unease about the unprecedented prospect of Congress removing a president from office: Clinton’s approval rating also rose during the deliberations over his impeachment (though Richard Nixon’s fell steadily throughout the Watergate investigation).

It’s also possible that Trump’s approval has edged up for a more traditional reason: More Americans are expressing satisfaction with the economy. This fall, as the stock market ascended and the unemployment rate plummeted to 3.5 percent, Quinnipiac University national polls found that the share of Americans describing the economy as “excellent” or “good” rose from 59 percent in September to 73 percent this month, according to its latest survey.

One of the key dynamics of Trump’s presidency, as I’ve written before, is that he faces more resistance from voters satisfied with the economy than previous presidents ever did. In that recent Quinnipiac poll, just 56 percent of those who described the economy as “excellent” or “good” said they approved of Trump’s overall performance as president, while 40 percent disapproved. By contrast, in both 2004 and 2012 roughly nine in 10 voters who said the same about the economy voted for the reelection of the incumbent president. (It’s worth noting that while Trump underperforms among voters satisfied with the economy, he still receives positive marks from most of them. As a result, as the share of voters expressing such satisfaction increased during the fall, that inexorably raised his overall approval rating as well.)

The leading Democratic super PAC Priorities USA is spending heavily in swing states with a message that the favorable economy has not translated into tangible improvements in living standards for average families. “I don’t think people feel like the economy is strong,” says Josh Schwerin, a senior strategist for the group. “They might be told that in the news and by Donald Trump, but when they look at their pay and their bills, they don’t feel it.”

Still, surveys such as Quinnipiac’s undeniably record substantial economic optimism: Roughly three-fourths of voters across multiple demographic groups—including African Americans, Latinos, and young people—say they are optimistic about their economic future. Assuming such attitudes endure through 2020, a key question for the election may be to what degree doubts about Trump personally—exacerbated by the Ukraine scandal—will suppress the gains he could ordinarily expect from such blossoming economic satisfaction.

The Quinnipiac surveys from this fall offer important hints at the answer. While the share of all Americans who described the economy as “excellent” or “good” jumped 14 percentage points from September to mid-December, Trump’s approval rating during that same period edged up just three points, from 40 percent to 43 percent. For several key groups, the gap between attitudes about the economy and attitudes about Trump substantially widened during that same period.

For instance, in the September Quinnipiac poll, the share of white college graduates who described the economy positively (66 percent) was 26 points higher than the share who approved of Trump’s job performance (40 percent). Now that gap has widened to 36 points.

Similarly, the gap between positive attitudes about the economy and positive attitudes about Trump widened from 14 to 35 points among Latinos; 25 to 39 points among African Americans; 19 to 34 points among young adults ages 18 to 34; and 19 to 35 points among adults ages 35 to 49. Over the fall, each group upgraded its assessment of the economy substantially more than it did its assessment of Trump.

Alan Abramowitz, a political scientist at Emory University, told me that attitudes about the country’s economic health have become more entwined with partisanship, with Republicans and Democrats alike more likely to grade it favorably under a president from their own party. But, Abramowitz adds, “with Trump you’ve also got the added factor that the negative perceptions of his character, personality, style, and also some of the policies that are pretty unpopular may limit any positive effects of an improving economy or a strong economy.”

Many groups Trump might hope to woo based on the economy remain deeply troubled by his behavior. Consider college-educated white voters. In the new Quinnipiac survey, fully 80 percent described the economy as “excellent” or “good,” and an equal number said they were optimistic about their financial future. But in the same survey, 53 percent disapproved of his job performance, 54 percent said Trump has abused the power of the presidency, and 66 percent said that asking a foreign leader to investigate a political rival is inappropriate. In a September Quinnipiac poll, 57 percent said Trump considers himself above the law. And in both CNN and ABC/Washington Post surveys this week, just under three-fifths of college-educated white voters said Trump behaved improperly in Ukraine. With young adults, the story is similar.

Even among white voters without a college degree, Trump’s core constituency, the results on these questions spotlight potential cracks for Trump, especially among women. While four-fifths of non-college-educated white voters express optimism about their economic future, and a clear majority oppose impeachment, about 40 percent say that Trump abuses his power as president and considers himself above the law. Given that Hillary Clinton carried only about one-third of these voters in 2016, these concerns suggest that Democrats could make modest gains with these voters, particularly women, who already moved away from the GOP in the 2018 midterm elections.

In many ways, the impeachment ordeal clarifies a central question looming over 2020: Will Trump’s reelection turn more on what is typical about his presidency or on what is unique and even aberrant? Typically, an incumbent president would expect to win reelection in an economy this strong, perhaps comfortably; that’s why most academic forecasting models that rely on economic factors project Trump as the winner. But no other modern president, except perhaps Nixon in the final months of his tenure, faced as many doubts about his honesty, ethics, and values. Nor did any other president show himself as determined to relentlessly polarize the electorate.

As the battle over impeachment shifts to the Senate, all of Trump’s assets are on display: unchallenged command over his party, passion among his supporters, and the lift from a humming economy. But equally apparent are his unbounded willingness to trample over political, cultural, and legal norms and the ferocious opposition to him that ignites. That’s the combination that has placed Trump’s reelection on a knife’s edge for 2020, despite an economy that might comfortably propel a more conventional president toward four more years.

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