In February 2000, George W. Bush’s presidential campaign was in peril heading into the South Carolina primary. John McCain had just scored an unexpected victory in New Hampshire, and his candidacy was picking up steam. The Bush campaign was fighting for its life. What happened next is political lore. Push polls and flyers began appearing around South Carolina that blatantly accused, or implicitly suggested, that McCain’s adopted daughter from Bangladesh was really “a Negro child” he fathered out of wedlock. The end result? Record high turnout, an 11-point Bush primary victory, and the stifling of McCain’s momentum that effectively ended his chances at securing the nomination.

Twelve years earlier, his father, George H. W. Bush, was facing similar dire circumstances. He was down 7 points to Democratic presidential nominee Michael Dukakis in August of 1988. But in September, the Bush campaign began attacking Massachusetts’s furlough program under Dukakis by running an ad about Willie Horton, a convicted murderer sentenced to life without parole, who raped a woman and stabbed her fiancé while on weekend furlough. The ad’s racial overtones were not lost on anyone. By October, there’d been a sea change in the polls and Bush was up by 10 points, a wave he rode to convincing victory.

While no single factor is solely responsible for these electoral outcomes, fanning the fires of racial division has long been an effective campaign strategy. Two hundred years before McCain was accused of having an affair with a black woman, Thomas Jefferson was denounced by the opposition as “the son of a half-breed Indian squaw, sired by a Virginia mulatto father.”

Donald Trump, the champion of a previous instantiation of the Obama birther movement, kicked the summer off by labeling Mexican immigrants as rapists and drug dealers. Ben Carson has compared Obamacare and abortion to slavery and declared that Islam isn’t consistent with the Constitution. Jeb Bush has blamed Asians for using “anchor babies” to hustle American citizenship. Chris Christie has associated a movement geared to draw attention to aggressive policing of black people with intentional black criminality towards police. Hillary Clinton was accused of using racial divisiveness when she said then-Senator Obama would be unable to win over the “hard-working Americans, white Americans” necessary to win the general election.

Political contests are emotional, high-stakes affairs and few topics stir up American passion like race. As a campaign strategy, race can have a polarizing effect that causes some voters to prioritize the issue when they wouldn’t otherwise, and impact voter turnout. More recently, the objective has been to drive up white-conservative voter turnout to counter the moderate and increasing liberal minority vote. Following Obama’s reelection, Rush Limbaugh argued that the Republican Party didn’t need better minority outreach to win elections, only higher white turnout. But does using race as a wedge issue really work?

Some scholarship suggests that racially coded appeals can indeed be highly effective. The late sociologist Hubert Blalock’s racial-threat theory is the most cited explanation for this phenomenon. It argues that when there is interracial competition for access to resources—like jobs, government funds, good schools, and safe communities—the race in power feels threatened by other races’ growing populations and political voice, and therefore takes measures to protect power and privilege. Studies have also shown that minority enfranchisement does indeed divert resources. In a National Bureau of Economic Research paper, Dartmouth professor Elizabeth Cascio and Yale professor Ebonya Washington found that the Voting Rights Act of 1965 caused a “significant shift in distribution of state aid toward localities with higher proportions of black residents.” When citizens become part of the political process, they gain the ability to claim its benefits.

But since the civil-rights era, explicitly racialized appeals to the electorate usually backfire on the candidates, largely because of societal norms surrounding racial equality. In short, explicit racism is a societal taboo with which many people, regardless of partisanship, don’t want to be associated. In her book, The Race Card, Tali Mendelberg argues that because politicians and voters want to adhere to this norm of social equality, some of them resort to employing and responding to implicit messages of racial resentment to maintain or increase political power and socioeconomic status. This is where the use of code words prove particularly useful in political communication—from Richard Nixon’s “law and order” to Ronald Reagan’s “states’ rights” to the euphemistic “urban” and “inner-city.”

But Nixon’s “Southern Strategy” saw little success when employed in its explicitly racist form. The 1970 midterm elections were an indictment of the strategy—Nixon’s race-baiting anti-busing campaign ended up hurting GOP candidates. He realized much more success with his “Suburban Strategy,” or “New Majority” approach of coded, colorblind appeals in 1972.

Perhaps no one understood this better than Reagan. During his 1980 campaign, memos reveal that he and his strategists employed a calculated approach: broadcast conservative messages to the public without appearing racist, reactionary, or hostile. This “Reagan Focused Impact” approach meant that while Reagan spoke of states’ rights to white, southern audiences, he also spoke of self-determination and local power to northern black audiences. As his strategists argued, this approach generated positive press for Reagan from all quarters—especially white moderates—and effectively neutralized attacks from black activists, making the racialized aspects of his campaign hard to pin down.

While Reagan still employed a form of racial divisiveness through the coded language of states’ rights or welfare queens (as he had done in the past), he also began to speak more of inequality and discrimination to black audiences. His campaign knew that in order to win the White House, politicians had to be more artful in their messaging since they could no longer rely on explicitly racialized tropes designed to stir white resentment.

But that may not be the case today with the rise of Trump and Carson. Their surge in the polls suggests that their use of race as a wedge issue proved beneficial to their campaigns.

The potential explanation of this is two-fold. First, the diversity of the Republican field—two Hispanic men, one black man, and one of Indian descent—has provided a convincing counter-narrative to any implication that the party is exploiting racial divisiveness for political gain. And second, that diversity does not extend to the Republican primary electorate, which, as of 2012, was over 90 percent white. Taken together, this means the use of racial divisiveness to increase white turnout can bear fruit while protecting its practitioners from charges that they are violating norms of social-equality. After all, how can supporting the black candidate mean a voter is interested in disenfranchising black people?

The result is a laundry list of policy positions on race-centric issues that have the effect of polarizing the electorate. For example, Republican candidates’ positions on immigration continue to evolve to the point that anything short of deportation and wall construction on the border is construed on the trail as support for amnesty. When voter-identification laws and the conservative principle of reduction in government size and services are taken together, they effectively reassign the power to distribute state aid, and limit its scale. Even affirmative action is returning to the U.S. Supreme Court for the third term in a row, an occurrence that raises doubt about the use of race in college admissions going forward. Each of these is symptomatic of the use of racialized appeals as a form of protectionism for dwindling resources.

It remains to be seen whether racial divisiveness as a campaign strategy can still help produce victories as it did in 1988 and 2000. It may be the case that it’s a useful approach in some primary contests, but quite damaging in a general election with a more diverse electorate. In any event, the use of such strategies does not mean that those who employ them are racists, but it does show a willingness to exploit societal ills for political gain. As Warren Rudd once said, “Desperate people do desperate things ... they grab on for anything they can get ahold of, and if it happens to be something nasty, rotten, and false, that doesn’t make much difference.”