Once upon a time, and not so very long ago, general elections didn’t matter in the South. There was never any suspense on the first Tuesday in November about who would become the next congressperson from North Carolina, the next senator from Alabama or the next governor of Georgia.

But it was not apathy that rendered general elections meaningless; it was instead the simple Southern fact of life that candidates’ fates were decided not on Election Day, but on Primary Day. Because—once upon a time—the Democratic primary was the election, and that whole business in November was just a formality.

Times sure have changed.

And The Rise of Southern Republicans, published in May by Belknap Press (a unit of Harvard University Press), documents just how much they’ve changed. Written by the “Black Brothers”—Asa G. Candler Professor of Political Science Merle Black and his twin brother, Earl Black, Herbert S. Autrey Professor of Political Science at Rice University—the book illustrates how the Grand Old Party’s inroads into Southern precincts have transformed American politics and given the United States its first national two-party system since the heyday of the Whigs in the 19th century.

“The Democratic party has always been a national enterprise, commanding durable strength in both the South and the North,” the brothers wrote. “Traditionally, the Republican party’s geographic reach was quite different. Apart from the short-lived Reconstruc-tion era, for many generations southern Republicanism ‘scarcely deserve[d] the name of party. It waver[ed] somewhat between an esoteric cult on the order of a lodge and a conspiracy for plunder in accord with the accepted customs of politics.’”

But beginning with the advent of the civil rights movement in the 1950s, white Southerners slowly began to identify themselves more and more with the Republican party, and when Ronald Reagan was elected president in 1980, that movement gained steam.

“It’s one of the most startling cases of party realignment I’ve ever seen,” Merle Black told a gathering of Atlanta political reporters in May, saying the shift reached its peak with the 2000 election, as Southern white conservatives migrated in droves to the Republican ticket. “For white moderates, there’s been a ‘dealignment’: the breakdown of the Democratic majority without another majority taking its place.”

Citing survey and exit poll data, the Blacks show that fully 70 percent of white conservatives identified themselves as Republicans in 2000; just 32 years ago, barely 20 percent of white conservatives identified with the GOP. Over the same period, the percentage of white moderates identifying themselves as Democrats has dropped from nearly 60 percent to just over 30 percent.

What all this means for national politics is that, to win national elections, the Republi-cans no longer are forced to draw massive majorities in Northern states to offset their equally large deficits in South. With more than 84 million people already and more arriving each day, the South is largest region of the country; three out of every 10 Americans live in the 11 states of the Confederacy.

“What’s going on here in the South is important [regionally], but it has tremendous implications for national politics,” Earl Black said. “The Republican party was invented as a party of the North—to unite the North to fight against the South—but now, for the first time since the 1830s and 1840s, we have a national two-party system.”