A striking portrait hung on the wall of the campaign headquarters for George H.W. Bush’s 1988 presidential run. It wasn’t a slick painting of the vice-president, who hoped to become the next Republican in the White House. Rather, it was a mug shot, a grainy photo of a black man with an Afro and a beard.

The man was William Horton, an escaped convict from Massachusetts who had been serving time for murder when he skipped out on a temporary furlough from prison and committed robbery, rape, and assault. Horton had never met Bush, but he was about to become the vice-president’s most powerful political weapon.

During the 1988 presidential election, Horton became a central figure in Bush’s campaign and a way for the candidate to imply that his opponent, Massachusetts governor Michael Dukakis, was soft on crime. His case stoked a debate on whether criminals should be allowed temporary furloughs from prison. When a political action committee used Horton’s mug shot in an attack ad, he became part of an infamous election-season strategy to stoke fear and racial anxiety among white voters.

In 1974, Horton was involved in the robbery and brutal stabbing murder of a 17-year-old gas station attendant, Joseph Fournier, in Lawrence, Massachusetts. Though Horton denies murdering the teenager, he was at the scene of the crime and was convicted of first-degree murder along with the other two men involved.

Horton, who was 23 at the time, was incarcerated at a Massachusetts prison and given a life sentence. He began to serve out his time in prison, until he was approved for the prison’s furlough program. In exchange for good citizenship, Horton took occasional furloughs to shop, attend church, or spend time with his daughter.

At the time, it was common for federal and state prisons to grant eligible inmates brief furloughs—usually for good behavior and depending on other factors like the amount of time they had served. Criminologists and corrections officers alike approved of the furlough system, which was believed to ease tension in the prisons.

In 1974, the New York Times reported on “the growing confidence that officials have in the furlough program, which they say has a high rate of success.” By 1988, UPI reported, one in ten state and federal prisoners had taken a leave from prison within the last year, and the majority of states and the federal government allowed prisoners who were serving life terms to leave prison temporarily.

The vast majority of inmates did not violate the terms of their furlough and returned to prison to serve more time. But when Horton was given a furlough in June 1986, he didn’t go back.

“I did something stupid,” Horton told The Marshall Project in 2015. He had been driving his nephew’s car without a license when he was pulled over. Instead of surrendering to police, he crashed the car and escaped, fleeing to Florida, then Baltimore.

In April 1987, he was arrested and convicted for entering a suburban Maryland home, attacking and tying up the male homeowner, raping the homeowner’s fiancée multiple times, and driving away with stolen goods.

To many who heard about Horton’s case on the news, his story was an example of how Massachusetts hadn’t been tough enough on its prison population. Why was a convicted murderer on the streets to begin with?

Al Gore, who vied for a spot on the Democratic ticket in 1988, had the same question. In a televised debate, he asked Michael Dukakis, then serving as governor of Massachusetts, a pointed question about Horton. The question, seen as a last-minute gambit for some political leverage, didn’t prevent Dukakis from securing the nomination.

But it did perk up the ears of Republican strategists. They, like Gore, knew that Dukakis had vetoed a bill that would have kept prisoners with first-degree murder convictions from getting furloughs. And they seized on the issue as a way to discredit their Democratic opponent.

“By the time we’re finished,” said Lee Atwater, who managed Bush’s campaign, “they’re going to wonder whether Willie Horton is Dukakis’ running mate.”

Soon, “Willie” Horton—renamed by Atwater—was frequently referenced by the Republican candidate on the campaign trail. Then, in September 1988, his photo was used in a brief attack ad that associated Dukakis with Horton’s actions. The advertisement alternated photos of Horton with photos of Dukakis and touted Bush’s support of the death penalty. “Weekend prison passes: Dukakis on crime,” declared the concerned-sounding narrator.

The 30-second ad was financed by the National Security PAC, not Bush’s campaign. It was designed to expose Dukakis’ policies on crime as weak, taking advantage of an issue that historically drove Republican votes. But it also used photos of Horton, including his mug shot, to panic prospective voters about black men and crime.

In one photo, Horton towered over a police officer; in another, his black-and-white mug shot was seen in contrast to color photographs of both white candidates. By the 1980s, the number of black prisoners in federal and state prisons was nearly 9 times larger than in the 1920s, and eventually black Americans would end up being incarcerated five times more than their white counterparts. If black prisoners were allowed out of prison, the ad implied, they would commit crimes as heinous as Horton’s in white communities.

Though the Bush campaign denied it was involved in the ad, it ran a similar ad, without photographs of Horton, shortly after. “More than likely,” writes historian Tali Mendelberg in The Race Card: Campaign Strategy, Implicit Messages, and the Norm of Equality, “the Bush campaign used the racial facts of the case intentionally—though subtly—as part of the overall strategy to recruit white voters without drawing the ‘racist’ label.”

Atwater, a Southerner, knew that masked appeals to race won elections. He recast William as "Willie," she writes. “Atwater was a white man raised in the Deep South…who was accustomed to referring to black men with overstated familiarity.”

"The fact is, my name is not 'Willie,' Horton later told the Nation. 'It's part of the myth of the case. The name irks me. It was created to play on racial stereotypes: big, ugly, dumb, violent, black — 'Willie'. I resent that. They created a fictional character — who seemed believable, but who did not exist."

By October 1988, the ad was replaced with another attack ad, then another that featured Horton’s victims but not his mugshot. By then, the “weekend passes” ad had already caught the attention of Jesse Jackson and Democratic vice-presidential candidate Lloyd Bentsen, both of whom decried it as racist. The Bush campaign denied the claims. “My advice to them is ‘grow up,’” Mark Goodin, Bush’s spokesperson, told the New York Times.

Nevertheless, the ad became infamous. Though the Bush campaign continued to deny any involvement in the TV spot, and Dukakis squarely lost the election, journalists and media scholars continued to dissect the advertisement, its origins, and its effect. In 1990, The New Republic reported that the PAC that aired the ad had submitted it without Horton’s mugshot, then secretively added it after the ad had been on the air for a few days. “This guy looked like an animal,” recalled Larry McCarthy, who developed the ad. Meanwhile, many correctional facilities stopped offering furloughs.

Still, argues political scientist John Sides, the ad may have had little impact on the election itself. Since the ad was only on TV for a short time in a limited market, writes Sides, it likely didn’t convince viewers to vote for Bush. “Could Dukakis have come from behind in October and won the election if not for the attacks on his record on crime? Sides asks. “We do not and cannot know.”

But 30 years after the ad aired, it is still seen as an example of how political ads can play on racism and fear. Even if the ad itself didn’t change the course of history, the questions it inspired have become part of it.