Democratic and Republican voters are further apart than they’ve been in a generation. Here’s why

Reporting from Washington  —  Barack Obama’s presidency appears to have profoundly shifted the voter coalitions behind the two major parties, with older and blue-collar whites moving to the Republicans as college graduates and secular voters have accelerated their shift to the Democrats.

The result, as this election season moves toward a snarling finale, is two parties whose voters differ more from each other than at any point in a generation, according to a new study by the nonpartisan Pew Research Center, based on interviews of some 8,000 voters this year.

That finding helps explain both the fraught tone of the campaign, with warnings from each side of catastrophe if the other wins, and the continued close nature of the contest. Donald Trump and Hillary Clinton both have weaknesses, but voting has become more and more tribal, and voters are unlikely to shift based on a particular candidate’s abilities.

About a third of voters currently call themselves independents — more than say they are Republicans and about the same share as those who call themselves Democrats. But the vast majority of those self-proclaimed independents actually lean either to the Democrats or the Republicans. Repeated studies have shown them to be reliably partisan in their voting behavior.

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Including those who lean one way or the other, the number of voters who identify with each of the two parties remains closely balanced, Pew found: 48% for Democrats and 44% for Republicans. That’s the same partisan division that existed four years ago, when Obama was reelected.

Underneath that steady division, however, change has taken place:

The Democrats have continued a rapid move toward greater ethnic and racial diversity, changing faster than the electorate as a whole. As the nation’s Latino and Asian American populations have grown, the Democrats have captured the lion’s share of their votes while retaining the loyalty of nearly nine out of 10 African Americans. The party has made strong gains among younger voters and among the growing number of nonreligious Americans and those with advanced education.

While the Democrats have gone broader, the Republicans have gone deeper, building support among their existing core groups — whites and older voters, especially men and those without college degrees.

The result: two parties sharply split along lines of culture, outlook and experience, divisions that go much deeper than political ideology for most voters.

Detailed results from the USC Dornsife/LAT daily tracking poll »

Democrats have become the party of the nation’s youthful, increasingly secular, racially and ethnically diverse urban population. Republicans represent an older America, both literally, given their backing from voters older than 50, and figuratively, with their support centered on white, religiously devout Protestants living in non-urban areas.

In each of those areas, the Republican advantage comes among parts of the population that are in decline.

Whites, for example, now make up 70% of the nation’s registered voters, down from 84% in 1992.

By contrast, the Latino share of the electorate has almost doubled in the last quarter century, from 5% to 9%, and continues to grow, as does the Asian population, now with about 2% of voters. The black share has risen slightly, from 10% to 12%. Democrats have consistently held the loyalty of more than six in 10 Latino voters and a similar percentage of Asian Americans, the Pew data show.

One part of the GOP coalition, in particular, whites without a college education, has become identified with Donald Trump, providing his most loyal supporters. But the GOP’s gains among that group started long before Trump entered the race.

Through the George W. Bush years, Democrats and Republicans ran roughly even among whites without college experience. But soon after Obama’s election, those voters started moving away from the Democrats in large numbers. The GOP now holds a 59% to 33% advantage among them.

The shift has been driven primarily by men. Almost two-thirds of white men without college degrees now identify with or lean to the GOP, while among white women without a degree, about half do.

Looked at another way, whites without a college education made up almost six in 10Democrats in 1992, the year Bill Clinton first won the White House. Now, as Hillary Clinton runs, non-college-educated whites count for just one in three Democrats. Their share among Republicans has dropped only slightly in that time, from 67% to 58%.

The Pew data do not show what motivated those voters to move away from the Democrats. Other research, however, has shown that Trump’s support corresponds closely to voters’ standing on measurements of racial animosity. That finding suggests that at least some of the shift in partisanship came in response to Democrats being associated in voters’ minds with the first black man to occupy to Oval Office.

While Republicans have gained ground among those without a college degree, Democrats have picked up support at the other end of the scale, a shift that began during Bush’s second term.

Since 1992, the share of Democrats with a college education has increased from about one in five to more than one in three. Among Republicans, the share with a college degree has remained steady and is now slightly below the Democratic level.

The trade-off, with Democrats gaining among the college educated while Republicans amass support among those without degrees, creates a long-term advantage for the Democrats because college graduates are growing as a share of the U.S. voting population.

About a third of voters now have college degrees, another third have some college experience but not a four-year degree and the remainder have not attended college. In 1992, half of voters had no college experience and fewer than one-quarter had a degree.

Along with those shifts along lines of race and education, the two parties have also divided by age.

Republicans used to be younger on average than Democrats, in part because for many years, Democrats depended on support from the generation that came of age under Franklin D. Roosevelt and the New Deal. But in the last couple of decades, as the World War II generation has passed away, older voters have become central to Republican electoral chances.

At the same time, voters 35 and younger, the millennial generation, have emerged as a key part of the Democratic coalition. Millennials, who are now equal to baby boomers as a share of the electorate, lean to the Democrats 57% to 36%. That’s partly because the generation is more racially diverse than older generations.

Even among white millennials, however, the Democrats have parity with the Republicans. By contrast, the GOP has the edge among all older generations of white voters.

The Republican edge among older voters and the Democratic advantage among younger ones affects another important part of people’s identity — religion.

Democrats have become the party of choice for the nation’s “nones,” as Pew refers to them — the rapidly growing and generally youthful part of the population who consider themselves agnostics, atheists or “nothing in particular” when asked about religion. Republicans have solidified the loyalty of the nation’s white, evangelical Protestants.

More than a third of those who identify or lean to the GOP are white evangelicals; almost three in 10 Democrats are nonreligious.

Among other religious groups, Catholics remain closely divided. Republicans have made gains among white Catholics, but those have been offset by the growth of the Latino Catholic population, which strongly favors Democrats.

Jews, by contrast, overwhelmingly favor the Democrats. Despite strains between the administration and some Jewish community leaders over policy toward Israel, about three-quarters of American Jews identify with the Democrats, a number that has ticked up slightly during Obama’s years in office.

The Pew study has a margin of error of 1.2 percentage points in either direction.

David.Lauter@latimes.com

For more on Politics and Policy, follow me @DavidLauter

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