In short, the essence of today’s GOP—overwhelming white and disproportionately Southern—was evident by the late 1960s. This is not, of course, the whole of the story. The evolution of the party and the broader racial geography of American politics would continue in fits and starts over the next 45 years. But unquestionably it was the civil rights movement, and white resistance to it, that put the Republican Party on its demographic and ideological trajectory. The following two tables underscore just how far the GOP has moved from its broadly centrist, racially liberal, geographically diverse base in the postwar period to the ideologically extreme, overwhelming white and disproportionately Southern party it is today.

In fact, it’s impossible to understand the modern Republican Party without understanding the white backlash of the 1960s. One of the central sources of continuity linking the Republican Party that emerged under Nixon in the late ’60s and early ’70s with the GOP of today is a sustained politics of racial reaction.

These politics were on full display in the 2012 Republican primaries, a half a century later, with the candidates seemingly trying to outdo one another in impugning the poor and African-Americans in particular. Newt Gingrich accused Obama of being a “food-stamp president” and opined that, “poor people should want paychecks, not handouts.” Rick Santorum was even more explicit when he offered up the following quote: “I don’t want to make black peoples’ lives better by giving them someone else’s money.”

Even Mitt Romney played the race card, blaming his defeat on the policy “gifts” that Obama had bestowed on the very “dependent” segments of the population he had alluded to in his notorious “47 percent” video. “Especially the African-American community, the Hispanic community, and young people,” he clarified, going into considerable detail about how specific policies benefited each group, thus effectively “buying” their votes.

The imprint of race and racism on today’s GOP is not only a matter of rhetoric. It was also reflected in the party’s transparent efforts to disenfranchise poor and minority voters in the run-up to the 2012 election. Throughout the country, Republican legislators and other officials sought to enact new laws or modify established voting procedures that, in virtually all instances, would have made it harder for poor and minority voters to exercise the franchise. From the beginning of 2011 through September of 2012, according to data reported by the Brennan Center at New York University, at least 180 bills restricting voting rights were introduced in 41 states. Ultimately, 25 new laws and two executive actions were adopted in 19 states, ostensibly to reduce voter fraud, although voter fraud has been a non-issue in the United States for decades. In total, these states represented 231 electoral votes, or 85 percent of the total needed to win the presidency.

On occasion, Republicans have owned up to the real aim of the new restrictions on voting. After orchestrating the passage of Pennsylvania’s especially restrictive voter ID law in 2012, Mike Turzai, the GOP leader of the state’s House of Representatives, couldn’t help but boast a bit. Said Turzai, “Voter ID, which is going to allow Governor Romney to win the state of Pennsylvania. Done.” Then there was the adviser to Ohio’s Republican governor, John Kasich, who defended the governor’s decree drastically limiting early voting, by saying that “we shouldn’t contort the voting process to accommodate the urban—read African-American—voter-turnout machine.” Most recently, a Republican official in North Carolina was forced to resign after touting ID cards as a way to reduce voting by “a bunch of lazy blacks that wants the government to give them everything.” But these rare admissions merely confirm what was already clear to any neutral observer. “The point,” as journalist Elizabeth Drew noted, was simply “to make it more difficult for constituent groups of the Democratic Party—blacks, Hispanics, low-income elderly and students—to exercise their constitutionally guaranteed right to vote.”

Stark as the racial politics of today’s GOP are, they’re just a continuation of views that have their roots in the 1960s. So even as we celebrate the civil rights movement and its string of remarkable campaigns and policy triumphs, we would do well to remember that today’s polarized America, and enduring racial divisions are also legacies of that very same struggle.