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WASHINGTON — The last decade was one of the most politically consequential in recent memory, one in which partisan divisions dominated. But under the surface, an enormous churn is redefining and re-sorting the two major parties.

A look at the numbers helps explain the larger story.

By events alone, the decade was tumultuous — from the Republican tsunami in 2010 to the rise of Donald Trump in 2016 and the Democratic correction in 2018. And yet, when you look at the percentage of voters who identify at a Democrat or Republican, the picture is one of stability.

In 2010, the NBC News-Wall Street Journal poll found that 42 percent of registered voters identified as Democrats, while 37 percent identified as Republicans. At the end of 2019, the figures showed 42 percent were Democrats and 37 percent were Republicans. Unchanged.

In other words, Barack Obama and Donald Trump may each be transformative presidents in their own ways, but viewed from 30,000 feet, the net effect of their time in office on the political landscape has been negligible.

Look a little closer, however, and the picture is much more fluid.

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Start with education. The last decade has seen noteworthy shifts among voters with and without a college degree.

Since 2010, those with a high school diploma or less as their highest level of educational attainment have moved markedly Republican. In 2010, 45 percent of those voters identified as Democrats and 34 percent as Republican, a Democratic lean of 11 points. By 2019, the numbers had flipped with only 35 percent identifying as Democrats and 40 percent identifying as Republican, a five-point lean toward the GOP.

But among college graduates the reverse was true. In 2010, college grads leaned Republican by 2 points, 41 percent GOP versus 39 percent Democratic. By 2019, college grads had become strongly Democratic, an 11-point difference — 34 percent Republican versus 45 percent Democratic.

Those are dramatic swings among big parts of the electorate that have impacts across the country. It’s a big part of the reason Democrats have increased their margins in highly educated urban areas.

The geographic divide that’s come to dominate the political discussion, the growing urban/rural split, is also visible in the NBC-WSJ poll data.

Rural communities have long leaned Republican, but the partisan gap has grown much wider in the last decade. In 2010, small-town and rural communities leaned Republican by five points, 42 percent GOP versus 37 percent Democratic. But by 2019, the partisan divide was 18 points in favor of the Republicans — 48 percent against 30 percent for the Democrats.

On the other side of the ledger, the Democratic Party’s growth among suburban women is abundantly clear in the numbers. In 2010, suburban women leaned Democratic by a small 3-point margin, 43 percent versus 40 percent for the Republicans. But the Democratic lean in 2019 had grown to 13 points, 47 percent Democratic versus 34 percent for the GOP.

And the last decade has brought big moves among some gender groups and ethnicities.

Men 50 or older have moved sharply Republican since 2010. They’ve gone from 41 percent to 37 percent edge to the GOP, to a 47 percent to 31 percent edge for Republicans. That’s a 12-point Republican gain among the group.

Women ages 18 to 49 have moved just as strongly in the other direction. Back in 2010, there was a solid 13-point edge for the Democrats among the group, 48 percent to 35 percent for the GOP. But in 2019 it was a 26-point partisan chasm — 52 percent identify as Democratic, compared to 26 percent who say they are Republican.

And Hispanics have seen some party I.D. movement as well, according to the NBC/WSJ numbers. In 2010, Democrats held a 35-point edge with the group, 57 percent to 22 percent for Republicans. In 2019, Democrats still held an edge, but it had shrunk by about 10 points — 50 percent of Hispanics said they were Democrats to 25 percent for Republicans.

Whether that trend continues will be an important story to watch as Hispanics become a bigger part of the electorate.

All the moves outlined here are big, double-digit swings and they are ultimately about a lot more than education or ethnicity, geography or gender. Voters in these various segments often live in different socioeconomic worlds. They face different sorts of challenges and they demand different kinds of policies from their leaders.

In short, American politics in the last decade might look like a consistent story of division and gridlock on the surface. But underneath, these shifts and others are remaking the parties on a fundamental level, changing what it means to be a Democrat or a Republican — and the process likely isn’t over yet.