Donald Trump campaigns in Raleigh, North Carolina, on Tuesday. Photograph by Sara D. Davis / Getty

Donald Trump might be borrowing the G.O.P. like a family car he can take for a joy ride and trash, but that doesn’t mean he’s flouting all of the family traditions. In many ways, he’s running a campaign that revives the old Southern strategy, practiced by Barry Goldwater and, more craftily, by Richard Nixon, of peeling disaffected white voters away from the Democratic Party with dog-whistle racism and a certain amount of sympathy for the lowered prospects of the working class. Trump is sure, naturally, that he’ll “do great” with that approach in the so-called solid South—solid for Democrats, from Reconstruction until the civil-rights era; solid for Republicans thereafter. Ahead of a campaign appearance in Raleigh on Tuesday, Trump declared, “People of North Carolina want strength, protection, and jobs, and President Obama and Hillary Clinton have let them down for many years. I will bring jobs back to North Carolina, and our country, like never seen before.”

As it happens, Hillary Clinton chose North Carolina this week for her first campaign appearance with President Barack Obama, and there’s a good reason for that: the South is no longer all that solid. In many places, North Carolina among them, Trump’s rummage-sale version of the Southern strategy is as likely to activate voters against him as it is to insure a G.O.P. victory. North Carolina’s state legislature recently passed a law that limited the rights of transgender people to use public bathrooms, but that law inspired a powerful movement against it: places like liberal Asheville, as the Washington Post reported last week, are “awash in rainbow heart posters that read ‘Y’All Means All,’ which hang in almost every storefront window.” An angry white man killed three Muslim students in Chapel Hill last year, but the Muslim community in the area proved vibrant enough not only to survive that assault but to launch new institutions, including a scholarship at North Carolina State, programs to aid Syrian refugees, and a local thrift store whose proceeds go to charities the victims supported. The state government is dominated by Republicans anxious enough about their hold on power to have instituted, in 2013, one of the strictest voting laws in the country (among other provisions, it bars people from registering and voting the same day, requires them to produce a photo I.D. at the polling station, and limits the time allowed for early voting). But Obama won North Carolina in 2008, and was only narrowly defeated there by Mitt Romney in 2012. Clinton is running ahead of Trump, by small margins, in most North Carolina polls.

Clinton sees North Carolina, rightly, as a legitimate battleground, for some of the same reasons that Virginia is one and that Florida, once a Republican stronghold, now swings Democratic. The electorate in those states is more diverse—Latino voters are a particularly important and growing element—and younger voters in those states are increasingly likely to vote Democratic. What’s also important, though, in loosening the Republican lock on the South is what’s known as in-migration—people moving from other states, especially in the Northeast, to growing metropolitan areas of the South, like the Research Triangle in North Carolina. Seth McKee, a political scientist at Texas Tech University, has published a series of articles on this phenomenon, including one, with M. V. Hood III, of the University of Georgia, called “What Made Carolina Blue?” McKee told me in an e-mail, “We found strong evidence that compared to any category of voter (Dem, Indie, Rep), in-migrants are notably more Democratic in their voting preferences and they are more likely to register as independents rather than partisans in a state with party registration. The continued in-migration only serves to advantage the Democratic Party because these populations come primarily from a much more Democratic region: the Northeast.” What’s more, McKee said, there has been “an impressive increase in the number of northern blacks migrating to the South (many of whom had parents and grandparents who left decades ago when the South was undergoing the growing pains of its post-Jim Crow reality).”

For an article published this year in the journal PS: Political Science and Politics, McKee and Jeremy Teigen, of Ramapo College, looked at this pattern throughout the South. They found a microcosm in one small northern Virginia city, Manassas Park, within the outer ring of Washington, D.C., suburbs, which has “a racially diverse demographic profile resembling the national average (i.e., 10% black, 30% Latino, and slightly more than 50% white)” and dynamic population growth owing to in-migration from the Northeast and the Midwest. While Manassas Park voted consistently for Republicans in the nineteen-eighties and nineties, it has since voted in steadily increasing percentages for the Democratic Presidential candidate, giving Obama sixty per cent of the vote in 2008 and sixty-two per cent in 2012.

“It may be true that within various regions of the United States, partisan sorting has contributed to greater political homogeneity and, on a macro-scale, has accounted for the large swaths of red and blue regions coloring the presidential map,” McKee and Teigen conclude. But there are important variations in the pattern. “When enough Manassas Parks are aggregated, a deep-red presidential stronghold such as Virginia turns purple and has an important role in shaping the outcome of presidential elections.”

There are exceptions to this tendency—Texas has not turned purple, let alone blue, despite an electorate with an increasing share of Latino voters and a good deal of in-migration. But there’s not enough solid red on the map for Trump, or the G.O.P., to rest easy—not even in the South.